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INSULATION | AIRTIGHTNESS | BUILDING SCIENCE | VENTILATION | GREEN MATERIALS

S U S TA I N A B L E B U I L D I N G

ALTERED CARBON

Hell’s kitchen


Why cooking can destroy indoor air quality

Net result

Bristol passive house makes an annual profit

Issue 33 £5.95 UK EDITION

Hampshire passive house beats RIBA 2030 embodied carbon targets


EDITOR’S LETTER

PA S S I V E H O U S E +

SAME HOUSE, DIFFERENT HOME.

2 | passivehouseplus.co.uk | issue 29


PA S S I V E H O U S E +

Publishers

Temple Media Ltd PO Box 9688, Blackrock, Co. Dublin, Ireland t +353 (0)1 210 7513 | t +353 (0)1 210 7512 e info@passivehouseplus.ie www.passivehouseplus.co.uk

Editor

Jeff Colley jeff@passivehouseplus.ie

Deputy Editor

Lenny Antonelli lenny@passivehouseplus.ie

Reporter

John Hearne john@passivehouseplus.ie

Reporter

Kate de Selincourt kate@passivehouseplus.ie

Reporter

John Cradden cradden@passivehouseplus.ie

Reader Reponse / IT

Dudley Colley dudley@passivehouseplus.ie

Accounts

Oisin Hart oisin@passivehouseplus.ie

Art Director

Lauren Colley lauren@passivehouseplus.ie

Design

Aoife O’Hara aoife@evekudesign.com | evekudesign.com

Contributors

Em Appleton Radouk Toby Cambray Greengauge Building Energy Consultants Marc Ó Riain doctor of architecture Peter Rickaby energy & sustainability consultant Jay Stuart sustainable design consultant David W Smith journalist

EDITOR’S LETTER

editor’s letter L

et me tell you this. This magazine’s purpose is to help steer as many people as we can to make their buildings as sustainable as possible. We’re not just publishers who happen to do a green building magazine, among other types of titles. We’re sustainable building advocates who happen to publish a magazine. That’s a critical distinction, and it is manifest in the pages of Passive House Plus. Forgive me if that sounds idealistic, but to quote the Swedish child upon whose shoulders such a huge burden has been placed: the world is on fire. I do not mean to grandstand or condescend, or to suggest superiority over other publishers. And I do not mean to add this context in the way that a bigot might say “I’m not being racist but” before launching into a nakedly racist tirade. But. Our motivation requires us to adopt an unusual approach for a magazine publisher. We have to describe sustainable building in a considerable amount of detail, because we won’t begin to address the confluence of environmental scourges that threaten to destroy our children’s future by glibly parroting poorly defined generalisations. That’s because the devil, in the efforts we all need to make to stop obliterating the conditions which sustain us, will be in the detail. That’s also why the team at Passive House Plus, insofar as we know how, attempt to exercise editorial judgement as to what kinds of approaches to buildings, and what kinds of specifications, we should choose to illuminate. Yet we also have to do so in a way that a disparate bunch of target readers, from clients to specifiers, tradespeople to policymakers, find engaging and useful. We’ve been publishing this magazine and its predecessor for over 16 years. We started out knowing little or nothing about sustain-

ISSUE 33 able building, but with a willingness to learn. As time has gone by and we’ve accumulated knowledge of which attempts at sustainable building have worked, and which have failed, you might expect the process of producing a magazine to have become easier. Nothing could be further from the truth. It’s not so much the case that the more we learn, the less we know. It’s rather that we’ve learned that, in order to affect change, we must provide our readers with a level of detail – and wrapped up in the most engaging, accessible way we can manage – that makes the production process of each issue, frankly, painstaking and extremely time-consuming. Which is a characteristically roundabout way of explaining why we’ve changed our publishing plans this year. In the past we have had delusions of getting magazines out on a bi-monthly basis. We’ve finally recognised the folly in this target, and decided instead to publish four seasonal issues of Passive House Plus per year, followed by a new publication: a yearly publication, tentatively titled the PH+ Building Performance Annual, which will revisit a selection of the circa 200 exemplar Irish and British case studies we have published over the years, and share quantifiable information on how the buildings have actually performed over time. I’m not being sanctimonious. But. Our work is about attempting to affect radical, rapid change in our buildings, and to do so by showing how, in as much detail as we can manage. We’re extremely grateful that so many of our readers have come to rely on us a trusted guide on how to design and spec out the kinds of buildings that work for today, without ultimately ruining the lives of our children in the process. Regards, The editor

Print

GPS Colour Graphics www.gpscolour.co.uk | +44 (0) 28 9070 2020

Cover

Hampshire passive house by Ruth Butler Architects Photo by Peter Langdown Photography

Publisher’s circulation statement: Passive House Plus (UK edition) has a print run of 11,000 copies, posted to architects, clients, contractors & engineers. This includes the members of the Passivhaus Trust, the AECB & the Green Register of Construction Professionals, as well as thousands of key specifiers involved in current & forthcoming sustainable building projects. Disclaimer: The opinions expressed in Passive House Plus are those of the authors and do not necessarily reflect the views of the publishers.

ABC Certified Average Net Circulation of 8,971 for the period 01/07/18 to 30/06/19

About

Passive House Plus is an official partner magazine of The Association for Environment Conscious Building, The International Passive House Assocation and The Passivhaus Trust.

ph+ | editor’s letter | 3


CONTENTS

PA S S I V E H O U S E +

CONTENTS

6

COVER STORY

32

22 06

INTERNATIONAL

12

NEWS

17

COMMENT Dr Marc Ó Riain reports on the seismic impact caused by the 1973 oil crisis; Dr Peter Rickaby assesses what the consequences are for the built environment, and the climate, of the lack of communication between research and industry; and builder Em Appleton asks what forms does sexism take in the construction industry, and what can we do about it?

4 | passivehouseplus.co.uk | issue 33

CASE STUDIES Net result Bristol passive house turns energy bills into net profits

A ground-breaking new passive house in Bristol makes superb use of an urban plot to create a bright and spacious home built from ecological materials that — thanks to its huge solar roof and Tesla battery pack — produces more energy than it uses, making it one of the first UK projects to meet the passive house ‘plus’ standard – while blitzing the RIBA 2030 Climate Challenge’s targets for both operational energy and embodied carbon.

This issue features an off-grid passive house situated on a ten-acre vineyard, in south-eastern Australia.

Passivhaus Awards open for entries, damning industry response to the Future Homes consultation, and Exeter puts passive house standard at the heart of its zero carbon plans.

40

32

Coasting home Beautifully designed Hampshire home breezes past passive standard

‘Architecture is the blissful moment when the site and brief come together,’ says architect Ruth Butler of the challenge she and her engineer husband faced in designing their family home, on a difficult urban site by the Hampshire coast. But it was a challenge they met and exceeded, because even though they hadn’t even planned to build a passive house, they soon realised the design was on course to meet the onerous energy standard anyway.


PA S S I V E H O U S E +

50

40

58

CONTENTS

62

Victoria falls 19th century home drops energy demand by 94%

This ambitious renovation and extension of a singlestorey Dublin redbrick, bringing it up to an A1 rating while far exceeding the new build NZEB standard, provides a beautifully-detailed blueprint for delivering warmth, comfort, and healthy indoor air — as well as extra space and living density — in historic city centre properties.

50

Double standards Mayo home takes passive approach to NZEB

62

The PH+ guide to: greener concrete

INSIGHT

66

MARKETPLACE

70

COLUMN

Sited on the side of hill, a new home that meets the nearly zero energy building & passive house standard in the west of Ireland boasts a locallymanufactured and super-insulated timber frame, and is designed to fold cleverly into the landscape rather than stick out from it.

58

Hell’s kitchen Why cooking can destroy indoor air quality

When it comes to air pollution, we tend to worry most about things like traffic fumes and solid fuel burning — or when it comes to indoor air, condensation, damp and mould. But one of the biggest threats in the air we breathe comes from something we are exposed to almost every day, but rarely think about: cooking. John Hearne reports on the evidence for how cooking affects indoor air quality, and what we can do about it.

Cement is responsible for up to 8% of global carbon emissions, and in this guide, sustainable design expert Jay Stuart looks at ways to minimise its environmental impact through good design, and at some of the alternative, lower carbon cement and concrete products on the market.

Keep up with the latest developments from some of the leading companies in sustainable building, including new product innovations, project updates and more.

How will we look back on the houses we are building today in the next century, and beyond? Toby Cambray, co-founder of Greengauge Building Energy Consultants, takes an imaginative look into the future…

ph+ ph+ | contents | contents | 5 | 5


INTERNATIONAL PASS I V E & EC O B UIL D S F R O M A R O UND THE WO RL D

6


I N T E R N AT I O N A L

AUSTRALIA

IN BRIEF Building: 118 m2 off-grid timber frame passive house Architect: Maxa Design Method: Timber frame w/ corrugated steel cladding Standard: Passive house certified

OUTTRIM VINEYARD PASSIVE HOUSE, VICTORIA, AUSTRALIA

Photos: Chris Neylon Photography

S

ited on a ten-acre vineyard in sunny south-eastern Australia, this elegant new off-grid passive house serves as a part-time residence for the farm’s two owners. The couple, who are both nearing retirement, were keen to build a home on the site to avoid endless one and a half hour commutes from Melbourne but were anxious to minimise the ecological footprint of any dwelling. The brief was to create a simple, modest one-bedroom dwelling to a tight budget, and with minimal impact on the vineyard. Some would argue that building a second dwelling is never truly sustainable, but designer Sven Maxa, of Maxa Design, says: “It has been said, that the most sustainable building you can build, is the one that you don’t build. If this is true, then building small is perhaps the next best thing.” As such, the finished house has a footprint of just 64 m2 and a floor area — excluding the basement wine cellar — of 96 m2. It has just one bedroom, plus a Japanese-style tatami room in the loft where guests can sleep, as well as a generous outdoor deck for sitting out on the mild summer evenings. Maxa says: “Marrying a very small footprint to the world leading passive house standard ensured a highly efficient home, powered entirely by solar PV and batteries, that has been constructed almost entirely of Australian FSC timber framing and corrugated steel cladding.” Indeed, the dwelling is fully off grid, with its own wastewater treatment system, rainwater collection, greywater recycling, and heat recovery ventilation unit. Ensuring the house could be fully powered by the 4.5 kW solar PV array meant that, in terms of kitchen appliances, the owners had to forego anything except a fridge, induction cooktop and oven. The airtight timber frame structure is insulated with glass wool, and windows are triple glazed timber units, clad in aluminium. Overall, the neatly detailed, farm aesthetic of the design provides a smart yet sensitive addition to the vineyard landscape. “Simplicity stands the test of time, and this design echoes that sentiment,” says Maxa. “There is nothing convoluted or contrived with this project, it is simply designed, simply detailed, with minimal interruption to the site.”

ph+ | australia international | 7


Simplicity stands the test of time, and this design echoes that sentiment.

8 | passivehouseplus.ie | issue 33


Insulation

Build something extraordinary inside and out

The Kingspan TEK® Building System is a simple, but revolutionary, way of building your dream home quickly and with outstanding energy efficiency. The Kingspan TEK® Building System comprises of 142 mm or 172 mm thick structural insulated panels (SIPs) connected with a unique jointing system for walls, roofs, and intermediate floors using I-beams or web joists.

Further information on the Kingspan range is available on: +44 (0) 1544 387 384 literature@kingspantek.co.uk www.kingspantek.co.uk Pembridge, Leominster, Herefordshire HR6 9LA, UK ®

www.kingspantek.co.uk/selfbuild

Kingspan, TEK, the House Device and the Lion Device are Registered Trademarks of the Kingspan Group plc in the UK and other countries. All rights reserved.


AUSTRALIA

I N T E R N AT I O N A L

10 | passivehouseplus.co.uk | issue 33


Environmentally responsible, low cost heating: Vitocal 200/222-A

One of the quietest monobloc units of its kind thanks to Advanced Acoustic Design Heating and cooling with a single appliance thanks to reversible circuit Up to 40% COâ‚‚ and 20% fuel saving compared to a gas condensing boiler Energy efficiency class: A++ / A (Type 221.A04: A+ / A) Internet-enabled with Vitoconnect (accessory) and free ViCare App Easy to operate Vitotronic control unit with plain text and graphic display No minimum distances between indoor and outdoor unit High DHW convenience thanks to 220-l integral DHW cylinder (222-A) For more information please see www.viessmann.co.uk/vitocal222

Viessmann Limited Hortonwood 30, Telford, TF1 7YP Telephone: 01952 675000 E-Mail: info-uk@viessmann.com


NEWS

PA S S I V E H O U S E +

NEWS PASSIVE HOUSE PLUS SWITCHES TO COMPOSTABLE WRAP

Passivhaus Awards open for entries

The new compostable Polycomp wrap.

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assive House Plus will now be delivered to subscribers in a fully compostable wrap for the first time. The new Polycomp wrap is made from a combination of starches, cellulose and vegetable oils. Polycomp can be disposed of on any compost heap, in a household garden waste bin, a household food waste bin, or it can be used to line your food bin. The wrap confirms to EN13432, the European standard for packaging waste compostability. It is compostable in open air as long as there are micro-organisms to break it down and is certified by TUV Austria to the ‘OK compost HOME’ standard. The OK compost HOME certificate guarantees a minimum of 90% of the material will compost in 12 months after the film is put into an environment with micro-organisms. Passive House Plus is already printed on paper certified by the Forestry Stewardship Council (FSC) and by a printer audited to ISO 4001, the environmental management standard. “We’re delighted to finally be making this change, which has been planned for some time,” said editor Jeff Colley. “We’re committed to minimising the environmental impact of Passive House Plus. It’s not just about publishing a magazine designed to steer the construction industry towards much higher levels of sustainability. We have to practice what we preach.” Colley added that the evidence shows that copies of Passive House Plus tend to be retained by readers for future reference. “According to our recent readers’ survey, just 6% of our readers in the UK and 3% of readers in Ireland said they bin or recycle the mag once they are finished with it, with the vast majority filing it away”. •

12 | passivehouseplus.co.uk | issue 33

Previous UK Passivhaus Awards winners include Hamson Barron Smith’s Carrowbreck Meadow, a 14-unit mixed tenure scheme in Norfolk, which won in the large residential category in 2018.

T

he 2020 UK Passivhaus Awards are now open for entries. The awards will celebrate the best certified passive house projects from across the UK. “We’re looking for groundbreaking schemes that will prove the [passive house] standard can tackle the climate crisis and create healthy environments. We want projects that not only have ambitious architectural ambition, but also impeccable performance credentials to prove it,” read a statement from organisers the Passivhaus Trust. The awards are open in three categories: small residential, large residential, and non-domestic. The small residential award is sponsored by Ecology Building Society. “Ecology supports UK projects that enhance the quali-

ty of housing and have a positive impact on the environment. Our sustainable mortgages incentivise the most energy-efficient properties such as those built to the passive house or Enerphit standards,” read a statement from Ecology.   “We anticipate another exciting range of entries this year, showcasing the latest innovation and design diversity that can deliver passive house, encouraging many others to adopt the standard. It’s always inspiring to see Ecology borrowers achieve success at these awards, which always receives a very high standard of entries.” Sponsorship opportunities are still available for the other categories. For more information see www.passivhaustrust.org.uk. •


PA S S I V E H O U S E +

NEWS

Damning response to Future Homes plans

T

here has been an overwhelmingly critical response from professional bodies and green building groups to the government’s proposed Future Homes Standard. The plans envisage no major upgrade to Part L of the building regulations — which covers energy efficiency — until 2025, with a less ambitious immediate update in 2020. Criticism of the proposals generally focused on two key points: that the proposals did not place sufficient focus on reducing energy demand in new dwellings, instead using carbon emissions as the preferred metric, and that the proposed timeframe was not ambitious enough. “In the context of a Climate Emergency, the proposed options for 2020 are not nearly ambitious enough and could actually result in a retrograde step,” said the Passivhaus Trust. The Trust criticised the proposed removal of the fabric energy efficiency standard (FEES), and said this was likely to lead to over-reliance on technologies like solar PV and heat pumps to reduce emissions from dwellings, rather than reducing energy demand through improved building fabric performance. It said: “…we could end up building houses which have a significantly worse fabric performance than those which we are currently building… The proposed backstop U-values are nowhere near good enough to ensure fabric efficiency.” The proposed targets for 2020 envisage minimum, wall, floor and roof U-values of 0.26, 0.18 and 0.16 respectively, and a worstcase airtightness of 8 m3/hr/m2. The Trust said the proposals represented a “conscious decision to move away from the fabric first approach”, and that the removal of the accredited construction details would mean there is “almost no restriction on the severity of thermal bridging as poor fabric can be compensated by PV or other non-fabric measures”. RIBA & CIBSE RIBA, meanwhile, also encouraged the government to set targets for operational energy use

in homes, to regulate the embodied carbon of buildings, and to close loopholes which allow developers to build dwellings to out-of-date standards. RIBA present Alan M Jones said: “The proposed  changes to building regulations  are simply not ambitious enough to meet the scale of our  environmental  challenge. If we are to stand a chance of meeting net zero by 2050, the government must urgently  embed  much clearer and more demanding targets on operational energy and embodied carbon into building regulations. “They must also crack down on loopholes which are exploited by developers to build new homes according to regulations from the time they first broke ground – often years out of date.” The Architects’ Declare initiative also said the plans represented “a step backwards just when we need to make a huge leap forward”. Meanwhile CIBSE said that “the timeline and content of the Future Homes Standard is not ambitious enough, nor does it begin to address real in-use energy performance and carbon emissions” and encouraged the government to “tighten requirements on the performance of buildings themselves”. It said that current proposal goes “very much in the wrong direction in terms of reducing energy consumption and peak demand, and also causes fuel poverty concerns.” CIBSE also stressed the government needs to link its plans for Part F of the building regulations, which covers ventilation, to Part L. “Part L and Part F are inextricably linked,” CIBSE said, “it needs to be clear that low energy and low carbon buildings will mean exemplary airtightness and appropriate ventilation to deliver good indoor air quality.” The UK Green Building Council also advised the government to shift the focus to building fabric performance and energy demand, and to begin phasing in requirements for the measurement of in-use building performance. It also called for the “assessment of whole life cycle carbon” for buildings, and for local authorities to retain the power to set tougher building standards locally.

S U S TA I N A B L E B U I L D I N G

Just three more reasons to advertise with us.

(above) RIBA president Alan M Jones said: “The proposed  changes to building regulations  are simply not ambitious enough to meet the scale of our  environmental  challenge.”

We could end up building houses which have a significantly worse fabric performance than those which we are currently building. This point was also echoed by the London Energy Transformation Initiative (LETI), a network of built environment professionals, which coordinated a response to the consultation and organised a petition signed by over 1,000 people, including 219 organisations. LETI shared many of the key concerns of other groups. “Fabric performance is likely to get worse,” LETI stated. “A home in 2020 could be less insulated than a home under 2013 building regulations. The use of an energy efficient heating system has the ability to mask fabric performance.” “Carbon and primary energy factors disguise the energy efficiency of a home. The energy consumption of a home can be high but carbon emissions low. This leads to inefficient homes which appear to be performing well.” •

77% 91% 83%

have made decisions on projects because of adverts in the magazine

said the products and services advertised are relevant to them

think of the brands that appear as some of the main brands in sustainable building

t +353 (0)1 2107513 | e jeff@passivehouseplus.ie | www.passivehouseplus.co.uk Source: Passive House Plus UK edition 2019 reader survey

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NEWS

PA S S I V E H O U S E +

Exeter places passive house at centre of 2030 zero carbon plans

Green concrete breakthrough with waste wood & recycled concrete

R

A

ll new buildings in Exeter City may be required to meet the passive house standard or equivalent, under an ambitious blueprint announced by the city council for carbon neutrality by 2030. The blueprint, product by Exeter City Futures for the local council, outlines an ambitious list of action points for transforming the city. These include making passive house or an equivalent standard the norm for all new construction, a widespread retrofit programme, and eliminating fuel poverty in the city. The plan also aims to reduce the dominance of cars in the city, and radically improve the experience for cyclists, pedestrians and public transport users. It envisages “excellent quality green space” within a ten-minute walk of every home, more land being reserved for local food production, and increased biodiversity and tree cover within the city. It also contains a detailed plan for cleaner air in the city. Exeter City Futures will now embark on a period of public consultation on the proposals. To read the blueprint in full visit www.exetercityfutures.com. Meanwhile, Exeter City Council has announced plans to build 92 new passive house certified apartments at Whipton Barton House, Vaughan Road, on the site of a former care home, which closed down four years ago. The existing buildings will be demolished to make way for the new passive house units, which will be arranged in three and four-storey blocks around the edge of the site, with green spaces and play areas in the centre. The project is being developed by Exeter City Living, a wholly owned development subsidiary of Exeter City Council. The new scheme of 92 apartments will include 60 affordable units and 32 for open market sale. Exeter City Council has been a leading champion of passive house building over the past ten years and now apply the standard to all newly built council dwellings. • (above) Renderings of the proposed scheme of 92 passive house apartments at Whipton Barton House, Exeter.

14 | passivehouseplus.co.uk | issue 33

esearchers at the Institute of Industrial Science at the University of Tokyo have developed a new procedure for recycling concrete with the addition of discarded wood. The research team found that the correct proportion of inputs can yield a new building material with a bending strength superior to that of the original concrete. This research may help drastically reduce construction costs, as well as slash carbon emissions. As countries work to constrain their greenhouse emissions, concrete production has fallen under increased scrutiny. Concrete consists of two parts, aggregate — which is usually made of gravel and crushed stone — and cement. Cement production is responsible for approximately 7% of global carbon emissions. "Just reusing the aggregate from old concrete is unsustainable, because it is the production of new cement that is driving climate change emissions," explains first author Li Liang. Therefore, a new, environmentally friendly approach is needed to help promote the circular economy of concrete. The researchers optimized their new method by adjusting the mixture proportion, pressure, temperature, pressing duration, and water content. Finding the right proportion of concrete and recycled wood was critical to obtaining concrete with the most strength. Wood gets its rigidity from lignin, which are highly crosslinked organic polymers. In this case, lignin fills the gaps in the concrete and functions as an adhesive when it is mixed with waste concrete powder and then heated. The material’s strength was also improved by higher temperatures and pressures during pressing. "Most of the recycled products we made exhibited better bending strength than that of ordinary concrete," says senior author lecturer Yuya Sakai. The recycled concrete is even likely to be biodegradable, because the concrete waste is attached to the wood component, the researchers said. The method could also be extended to recycle other types of discarded plant matter, instead of wood, or even brand-new concrete made from plants, sand, and gravel. This research will be published in the proceedings of the Sixth International Conference on Construction Materials (ConMat'20) as ‘Experimental study of the bending strength of recycled concrete and wooden waste by heating compaction’. •

Just reusing the aggregate from old concrete is unsustainable, because it is the production of new cement that is driving climate change emissions.


PA S S I V E H O U S E +

NEWS

Embodied carbon calculation to become a feature of Passive House Plus in framing and standardising the parameters for LCAs. With a new impetus on designers to think and act in terms of quantifiable sustainability indicators – such as the ambitious targets for operational and embodied carbon emissions set out in the RIBA 2030 Climate Challenge, which also references the RICS report – the hope is that readers will engage with the detailed examples shown in Passive House Plus case studies, and start using LCA tools to influence the decisions that are made on their own projects. •

Embodied Co2e: completion vs end-of-life

Carbon Emitted >

600

kg CO2e/m2 NIA

he publishers of Passive House Plus have committed to including life cycle assessments (LCAs) of buildings featured in the magazine, including the publication of cradle-to-grave embodied carbon scores. While there are many ways in which buildings impact on the environment, up till now many of these impacts have proven hard to quantify, and the process of conducting an LCA has tended to be time-consuming and nebulous. Consequently LCAs have typically only gained a foothold when large, non-domestic buildings are being certified to sustainability rating standards such as BREEAM or LEED – most often as an exercise upon completion, rather than at design stage, meaning the opportunity to compare and adjust specifications to reduce environmental impacts is lost. Values such as embodied CO2 scores for the building are rarely published. The broader industry therefore remains in the dark about how green or not a given project truly is, and the opportunity to affect change is lost. But the advent of new tools such as PHribbon – developed by Optimal Retrofit for the Association of Environment Conscious Building, to integrate into the Passive House Planning Package software – offers the prospect of conducting speedy, accurate LCAs for buildings, provided the designer can provide detailed specifications for a proposed building. Passive House Plus arranged for two of the four buildings profiled in this issue – passive houses in Hampshire and Bristol – to have LCAs done by Tim Martel of Optimal Retrofit. “We plan to include LCAs for every building we publish, where possible,” said Passive House Plus editor Jeff Colley. “As we have learned with operational energy performance, the development of credible tools to quantify performance in terms of kilowatt hours for space heating demand, airtightness levels, temperatures etc., have been crucial in terms of objectively assessing a building’s performance, and setting benchmarks for improvement. The greenness of building materials, by contrast, has seemed much harder to pinpoint, with specifiers too often reliant on competing claims from suppliers. That’s finally starting to change.” Colley said that the growing number of construction product manufacturers obtaining Environmental Product Declarations – which contain independently audited and validated figures for a long list of environmental impacts associated with a given product – has been a crucial breakthrough, along with the development of affordable, simple software tools for designers. “But it’s critical that we’re comparing like-with-like,” said Colley, adding that the Royal Institute of Chartered Surveyors (RICS) 2017 report, 'Whole Life Carbon Assessment for the Built Environment', is a key document

400

200

0 < Carbon Stored

T

C: End of life B: Use phase A4/A5: Transport/construction PV

-200

Plasterboard Windows Concrete Brick

-400

Oil based

Cradle to practical completion

Cradle to grave

Timber

NEW CAMPAIGN FOR SCHOOLS AND UNIVERSITIES TO GO PASSIVE

T

he Passivhaus Trust has launched a new campaign for 2020 to promote the adoption of the passive house standard in educational buildings. Aimed at those in the education sector, the campaign intends to encourage the adoption of passive house principles and provide guidance to clients on the process of procuring buildings to the standard. The campaign applies to all educational buildings from primary and secondary

schools to university research facilities, and even student accommodation. It will follow a similar format to the Passivhaus Trust’s positively received social housing campaign last year. The trust intends to run three regional events throughout the year, and to develop a guidance document outlining the business case for adopting the standard, and factors that will improve success and cost-effectiveness.

The campaign will also highlight the benefits of the passive house standard for occupant comfort and learning outcomes in schools. It will also aim to engage with the Department of Education on the design of educational buildings. The first regional event of the campaign takes place in Edinburgh on 14 May. Further events are planned for Wales and London. For more information see www. passivhaustrust.org.uk. •

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NEWS

PA S S I V E H O U S E +

RIBA LAUNCHES ENERPHIT GUIDE

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IBA has published a new in-depth guide to the Enerphit Standard, the Passive House Institute’s benchmark for retrofit projects. ‘EnerPHit: A step by step guide to low energy retrofit’ is written by architect James Traynor, and it “provides architects and designers the tools to retrofit our existing buildings to demonstrate what is possible and help the UK meet its crucial carbon reduction commitments”. Equipping the reader with key information on Enerphit, the book aims to give both architects and policymakers a practical understanding of the standard. Backed with real-life case studies, the book “enables architects to understand how to achieve successful outcomes that are tailored to suit available budgets and programmes”. James Traynor is managing director of ECD Architects, which has been at the forefront of sustainable design since 1980. He is a certified passive house designer and has led several important retrofit projects, including the pioneering Enerphit upgrade to Wilmcote House, a large social housing block in Portsmouth. “Enerphit, pioneered by the Passive House Institute, is the gold standard of performance for existing buildings. To meet the ambitious target of reaching carbon zero by 2050, or much earlier, building owners across the UK will be required to upgrade their buildings to adhere to increasingly stringent energy performance requirements,” read a statement from RIBA Publishing. “So far, there has been no clear advice from UK Government on how these requirements can be achieved, but the Enerphit standard offers a very clear methodology. “Nearly 20% of UK carbon emissions are attributed to the heating and cooling of buildings. By tackling our inefficient stock, we can address both carbon emissions and fuel poverty, whilst providing improved thermal comfort and a healthier environment.” The book is available from www.architecture.com. •

Devon passive house plus scheme wins property award

The Seaton Beach apartment building.

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development of luxury passive house apartments in Devon has won the award for best sustainable residential development in the UK, in the International Property Awards. Seaton Beach, a five-storey scheme of eight apartments, is certified to the passive house plus standard, which means that as well as meeting the classic passive house standard, it must also generate a substantial amount of renewable energy on site. Designed by leading passive house architects Gale & Snowden, the scheme features a Porotherm hollow clay-block wall system – a thermal block system which required no additional insulation in this case to meet the passive house standard – along with Norrsken triple glazed windows and doors, Isokorb balcony connectors, Genvex exhaust air heat pumps, and an extensive solar photovoltaic array. Apartments in the scheme start from £524,000. The award judges praised the scheme’s “striking, contemporary, yet sympathetic design”. Mike Webb, managing director of developer Seaton Beach, said: “To be recognised by our industry peers for our [passive house] apartment block is a great honour. “Not many UK developers build to this standard from Germany – now over 30 years old and globally recognised. “We could have taken the traditional route, however we believed it was the right way forward for the environment.” The project is set to be the subject of a substantial case study in a forthcoming issue of Passive House Plus. •

16 | passivehouseplus.co.uk | issue 33


COLUMN

EM APPLETON

Are you sexist? Creating a building site culture where we can all thrive

What forms does sexism take in the construction industry, asks builder Em Appleton, and what can we do about it?

I

imagine you are a pretty great person. You’re reading this magazine, so you clearly care about the building industry, maybe you are a bit of a change-maker, a pioneer in your field, or simply someone who cares about this planet and wants to make a difference. I imagine you care about women and men equally too and believe that women are just as capable of being a tradesperson as a man. You may have worked with women on site, or perhaps you actually are a woman. Perhaps you would even call yourself a feminist. Scholar and writer bell hooks describes feminism as “a movement to end sexism, sexist exploitation and oppression”. She consciously coined this definition in her book ‘Feminist Theory: From Margin to Centre’ in order to clarify that the problem she is identifying is not men. The feminist movement is not anti-male. The problem is sexism itself. Sexism is something that impacts us all

Sexism is something that impacts us all.

and is within us all. The definition coined by bell hooks invites us to look inward at how we all have, regardless of our gender, been socialised from birth to accept sexist ways of thinking and acting. As a consequence, men, women and nonbinary humans can all be just as sexist as each other. We all are impacted negatively by the way that institutionalised sexism (aka “the patriarchy”) is embedded into our culture. The patriarchy requires both men and women to act in a certain way. For instance, when a little boy cries or a man shares his feelings, their masculinity is called into question and they are discouraged from such behaviour. Sexism requires men to be tough and strong and not to share their feelings, even when that is a matter of life and death. The male-dominated construction industry has the highest suicide rate of all employment industries in the UK. The Office of National Statistics found that the suicide risk for low-skilled male construction workers is 3.7 times the national average. I believe that

this tragically high suicide rate is influenced directly by the macho culture that includes a lack of support for men to speak about feelings of depression and failure. Despite this huge impact on our lives, sexism is elusive, and it takes a conscious commitment to root it out and name it for what it is. Sexism is normalised in our lives to the point that it is so transparent that we don’t even recognise it. Tema Okun, in the report ‘White Supremacy Culture’ , says “culture is powerful precisely because it is so present and at the same time so very difficult to identify”. Being a woman does not automatically make someone a feminist and owning a woman-run construction business does not automatically eradicate sexism on site. This is why journalist Susan Faludi points out that “you can’t change the world for women by simply inserting female faces at the top of an unchanged system of social and economic power”. Or as Charlotte Bunch wrote in her essay ‘Class and Feminism’, “you can’t just add women and stir”. Often, I have to stop and check myself before I assume that a man, any man, will be better, more accomplished and more experienced than I will be on site. This thought comes into my mind even after the ten years that I have been working on the tools. This same unconscious bias against women plays itself out when a man takes a tool from my hand to complete a task I am in the middle of… because he is trying to help. And when a new tradesperson arrives on site and assumes that I am the client or the contractor’s wife, rather than the person running the site. And again, when a man assumes the idea spoken first by a woman is his, and it is his voice that is published. This unconscious bias against women cannot be separated from the violent acts of sexual harassment and bullying that also happen in our workplaces, and which can prevent women from feeling safe in male-dominated spaces. Therefore, while many of us would resist and stand up against these overtly discriminating violent acts of sexism, we also need to do the work of uncovering the invisible sexism that is within each of one of us. So, I will answer the question. Yes, I am sexist. And so, probably, are you. And with that admission it is time to do the

work, in our workplaces and on our building sites, of ending sexism, sexist exploitation and oppression. It can only be of benefit to all of us to ask the question: “what does a feminist building site look like?” This work isn’t glamorous. It’s going to take a lot of time, questioning and reinterpreting the long-held beliefs and values that we have been taught for generations. None of us get to be the knight in shining armour. And for a cis1 white man, a lot of the time, the work may be to keep silent and make space for women, nonbinary people and people of colour to share their voices, voices that have largely been silenced in our industry. As Jennifer Armbrust (www.sister.is), the feminist business consultant, says: “to do something as audacious as call your business feminist requires showing up every day with humility, heart, intrepid creativity, criticality, courage, self-love and a passion for growth. It requires accountability to yourself, your business, and to the larger social project of dismantling patriarchal and oppressive systems.” For my part, I am excited to take on this experiment and begin to explore what a feminist, anti-oppressive, healthy and inclusive building site looks like. I have begun with my list of “100 ways to create a feminist building site”, which you can find on my website at www.emappleton.com/culture. Of course, there could easily be 100 more. And I would love to hear your 100 ways if you fancy sharing them with me. n

1

c is or cisgender (sometimes cissexual, all abbreviated to cis) is a term for people whose gender identity matches the sex that they were assigned at birth. For example, someone who identifies as a woman and was assigned female at birth is a cisgender woman. It is the opposite of the word transgender.

A fully referenced version of this article is online at www.passivehouseplus.co.uk

ph+ | em appleton column | 17


MARC Ó RIAIN

COLUMN

The first oil crisis In the latest instalment of his series on the development of energy efficiency and renewable energy in the 20th century, Dr Marc Ó Riain reports on the seismic impact caused by the 1973 oil crisis.

W

estern culture was irrevocably changed by the oil crisis of 1973. The embargo by the Organisation of Arab Petroleum Exporting Countries (OAPEC) may have failed, but it changed the global political order, international government policies, and the cars we drive. It would turn out to be the key factor in future research for renewable energy and building energy conservation. Before 1973 we drove big cars, paid little for fuel and built houses with little concern for energy conservation. Whilst the UK had introduced building standards from 1959 to 1972, Ireland failed to do so until 1992. Whilst voluntary standards existed, they were relatively poor, as political priorities were driven by cheap and abundant oil. Public and environmental opinion towards fossil fuels and nuclear power had started to shift, with the negative pollution and human impacts of the Aberfan coal heap collapse (1966), the Windscale nuclear reactor fire in Wales (1957), the Torey Canyon oil spill off Cornwall (1967) and the Santa Barbara oil spill (1969). The subsequent establishment of the EPA in the US in 1970, Greenpeace in 1971, the first UN Conference on Environment in 1972, and the Green Party in the UK in 1973, all reflect a tectonic shift in both government policy, public opinion, and the lobbying power of the environmental movement.

every other day with the even/odd car number car plate rationing rule, speed limits of 55mph and Sunday driving bans were introduced, together with year-round daylight savings. The public suddenly started to become acutely aware of their energy consumption for the first time. One result was a public shift away from large, less economical cars, resulting in the popularity of the hatchback (the Fiat 127 was originally produced in 1971, the Renault 5 & Peugeot 104 in 1972 and the VW Golf in 1974). The sudden depletion of oil reserves threatened national economic and societal collapse. Gross national product (GNP) and increasing unemployment were a direct result, bringing industrialised countries to their knees. In February 1974, Richard Nixon and Henry Kissinger led an international energy conference in Washington attended by the 24 OECD member countries representing 85% of net oil consuming countries, including the United Kingdom and Ireland. Coming out of the conference, Nixon adopted a US policy for energy self-sufficiency, entitled Project Independence 1980. This policy became central to both US and UK domestic and foreign policy for nearly two decades. Both nations pivoted towards greater oil exploration and fracking in Alaska and the North Sea. Out of the same conference came the formation of the International

lifted, the entire geopolitical landscape had been utterly redrawn, forcing the west into action over the ‘oil weapon’. A political motivation, the 1973 oil crisis, rather than the environmental movement, was the critical driver of international energy conservation and renewable policy. Pragmatism rather than ideology won the day… certainly a lesson for the Green Party and those of us who support environmental policies today. My next article will focus on early zero energy buildings in the 1970s. n

above A US petrol station with no fuel to sell during the 1973 oil crisis. Photo by David Falconer, US EPA

The sudden depletion of oil reserves threatened national economic and societal collapse. In October 1973, as people were filling their home heating tanks with oil for the equivalent of $3 a barrel, an Egyptian and Syrian offensive against Israel resulted in the Yom Kippur War. The Israeli rout of the Egyptian 3rd army at Suez was supported by arms from the US and its allies. An angry OAPEC placed an oil embargo against the Western countries supporting Israel, gradually closing the tap on their oil supply up to 25% by December 1973, resulting in the UK and US being seriously depleted. As a result, the price of oil increased 400% from $3 to $12 by 1st of January 1974, with petrol stations and home heating quickly following. People could only refuel their cars

18 | passivehouseplus.co.uk | issue 33

Energy Agency in November 1974. As part of the energy conservation responses, building energy conservation standards in the UK were revisited and improved. Ireland created a non-statutory set of building energy standards close to that of Scotland. Most governments stepped up R&D on renewable energy, to reach a peak in 1980, followed by decline thereafter; Denmark heavily invested in combined heat and power with district heating. Sweden focused on nuclear power, biofuels and hydropower, reducing manufacturing industry oil consumption from 48% to 10% . Although by April 1974 Israel had withdrawn from the Suez Canal, and the embargo was

Dr Marc Ó Riain is a lecturer at the Department of Architecture at Cork Institute of Technology, one of the founding editors of Iterations design research journal and practice review, a former president of the Institute of Designers in Ireland, and has completed a PhD in low energy building retrofit, realising Ireland’s first commercial NZEB retrofit in 2013.


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PETER RICKABY

COLUMN

Culture shock & knowledge transfer What are the consequences for the built environment, and the climate, of the lack of communication between research and industry, asks Dr Peter Rickaby – and what can be done about it?

D

uring the 1980s I was a university researcher, overlapping with thirty-five years as an energy and sustainability consultant. Last year I returned to academia to help run a university-based technical centre, and the transition has been a culture shock. I am impressed by my academic colleagues’ knowledge of energy and buildings, but astonished that little of it reached me in my consultancy. I observe that for many academics the goal is to discover and publish new knowledge (in competition with each other) rather than to make a difference in the world outside. Much of that knowledge is published in conference proceedings and academic journals, but those are not the places that building professionals usually look for information. Equally, many technical issues that professionals would like to address are not on the academic agenda. The worlds of research and practice seem to exist in parallel and acknowledge each other, but

professionals about the technicalities of designing energy efficient buildings. Similarly, Dr Wolfgang Feist established the Passive House Institute (PHI) to bring more technical rigour to the design of energy efficient buildings, through the passive house standard. The Centre for Alternative Technology (CAT) in Wales has for many years offered UK and Irish building professionals masters’ degrees in energy-related subjects. A few years ago, the Institute for Sustainability (IfS) and the Centre of Refurbishment Excellence (CoRE), although both short-lived, collated knowledge and expertise in building retrofit, and disseminated it via guidance and training respectively. Most recently, at UCL, Neil May challenged his academic colleagues to make their work more useful, and simultaneously encouraged building professionals to take more note of formal, evidence-based knowledge – an exhortation that led to the establishment

Faced with the climate emergency, we urgently need to bring academic research and industry knowledge together.

not to communicate effectively. In the academic world, research is driven by the quest for knowledge, which must be evidence-based; in practice, knowledge is often based on experience and driven by a need to solve a problem in a timely and profitable manner. Faced with the climate emergency, we urgently need to bring these two types of knowledge together to make a real difference — but making the connection can be challenging. Many attempts have been made to bridge the gap. In the 1990s, the government-funded Building Research Energy Conservation Support Unit (BRECSU) based at BRE established the housing energy efficiency best practice programme with a brief to research best practice and communicate it to industry. The research was rigorous (at least initially) and the output was dozens of good practice guides and case studies, promoted by thousands of seminars, workshops and short courses, across the UK. At UCL, the Energy Design Advice Scheme (EDAS) sought to advise

20 | passivehouseplus.co.uk | issue 33

of the independent Sustainable Traditional Buildings Alliance (STBA) and of the UK Centre for Moisture in Buildings (UKCMB). The value of bodies like BRECSU, EDAS, PHI, CAT, IfS, CoRE, STBA and UKCMB (and other examples) is that their role is to promote communication between the research world and industry. They are engagement and impact mechanisms. Universities have long been encouraged by governments to engage with industry. Most universities have a department, centre or institute for this, but instead of pursuing engagement and impact through communication there is perhaps too much emphasis on patenting and commercialising academic innovations, on incubating ‘spin off’ companies and on seeking industrial sponsorship. These may be legitimate activities, but the purpose of engagement is to make an impact, not to make money. In the UK, perhaps the most successful mechanism for this is the Knowledge Transfer Partnership (KTP), in which researchers are placed in

and part-funded by industry. My consultancy company had a KTP; the researcher spent three years with us, helped us to think beyond our usual practice, improved our methodology for dealing with a practical problem and completed his doctorate. He then worked for us for two years before developing a successful international career in commercial knowledge transfer. All buildings-related university departments should be encouraged to develop KTPs for engagement and impact, and all professional consultancies, product suppliers and construction companies should be encouraged to consider KTPs as a way of bringing new knowledge into their businesses. Perhaps, if we can do that, moving between the two worlds will not be so much of a culture shock. Finally, I have discovered a small and informal but inspiring organisation that seeks to bring together the knowledge, skills and commitment of individual academics, professionals and others from many backgrounds. It is the MaD (Make a Difference) network recently established in London and now spreading to other parts of the UK and Ireland – check it out at www.madnetwork.net. n

Dr Peter Rickaby is Principal Research Associate at the UK Centre for Moisture in Buildings, and chairs the BSI Retrofit Standards Task Group. He was BSI’s technical author for the new domestic retrofit standard PAS 2035 and is now working on the nondomestic retrofit standard PAS 2038.


BRISTOL

CASE STUDY

22 | passivehouseplus.co.uk | issue 33


CASE STUDY

BRISTOL

ENERGY BILL

£162 PER YEAR PROFIT

(see ‘In detail’ for more)

Building: 153 m2 detached timber frame house Location: Bristol Standard: Certified passive house plus

N E T R E S U LT B R I STO L PAS S IV E H O U S E TU RNS ENER GY BILLS INTO NET P ROFITS

ph+ | bristol case study | 23


BRISTOL

CASE STUDY

A ground-breaking new passive house in Bristol makes superb use of an urban plot to create a bright and spacious home built from ecological materials that — thanks to its huge solar roof and Tesla battery pack — produces more energy than it uses, making it one of the first UK projects to meet the passive house ‘plus’ standard, while also blitzing the RIBA 2030 Climate Challenge’s targets for operational energy. Words by Kate de Selincourt

A

s we get older, many of us feel the cold more, especially if disability leaves us inactive. So if you are planning a home that you’ll be able to live in comfortably for a very long time, it makes sense to build a passive house. However when Bristol residents Janet and Bernard decided to make their new home a passive house, their thoughts were very much turned outwards: to future generations, and to doing the right thing by the planet. Janet and Bernard were living in an ideal location for their retirement, in a busy neighbourhood centre on the fringe of Bristol. Shops, libraries, doctors, buses – everything was on the doorstep. But now that their children had grown and started families of their own, their family home was too big. And they knew from personal experience that their house, product of more than 200 years of extension and alteration, was completely unsuitable for anyone with disabilities. Janet’s mother had become infirm and lost mobility as she aged, but try as they might, they could not accommodate her: “All the doorways were narrow, and everything was on different levels, up and down steps,” Janet recalls. “We wanted to move to a home where we could stay if we were to become infirm ourselves, so we started looking locally for something more suitable” — but without much success. An estate agent they consulted about selling their house pointed out that potential buyers looking at the large garden, in such a convenient location, would immediately apply for permission to build one or even two new dwellings there. After the initial shock that Janet’s muchloved garden might be destroyed by a stranger’s digger, a solution presented itself: they could develop the garden themselves. That way they could design a truly all-ages friendly home, continue to enjoy every single advantage of the location, and even retain a little of Janet’s planting. But as well as having a ‘lifetime home’, Janet and Bernard had another overriding priority: “We were committed to the new home being green. It’s really important for the next generations to leave that legacy.” So, the couple set about finding out exactly what ‘green’ meant. “We found that some of the things that are described as ‘eco-friendly’ weren’t really so eco-friendly after all.” The couple spent “an awful lot of time on the internet”, but a breakthrough came when an acquaintance in the construction industry advised them that the key to getting a genuinely eco-friendly building was to get a

24 | passivehouseplus.co.uk | issue 33

really good builder. “He warned us that most builders would not build to the standard we wanted,” Janet says. On this basis they identified Bristol-based construction firm Greenheart Sustainable Construction as a firm who really understood sustainability. “Greenheart were very clear that building a high performance, genuinely low footprint building would cost more. They wanted to make sure we understood — I think Malcolm was interviewing his clients!” They brought their preliminary design to Greenheart and asked them to quote to build it. Greenheart’s Malcolm McMahon got a good sense of Janet and Bernard’s commitment to genuine environmental perfor-

He warned us that most builders would not build to the standard we wanted.

mance – and after looking at the initial design proposals told them that he did not believe the design would achieve what they wanted. However, Malcolm knew a couple of people who could help. Greenheart share an office with passive house consultant Piers Sadler and architect Jeremy Dain, so Malcolm suggested the couple seek their design advice. “Our target was to be eco-friendly without going mad,” Janet says. “Piers explained to us that our initial design was too complicated and had a lot of glass on the north side. It was not thermally efficient and would be complicated to build.” Embracing passive house The couple were not especially set on any particular standard, but recognised that the timber framed passive house approach being recommended to them would deliver a home that would be comfortable, extremely low impact, and have low running costs. As Greenheart’s Richard Hatfield recalls: “They were very open-minded. While they weren’t specifically interested in passive house to begin with, they researched a lot and learned a lot, and embraced it really.” Architect Jeremy Dain agrees: “Having a client keen to build an exemplar building


CASE STUDY

Photography: Alan Russell / Zed Photography

a higher-performance foam to the same U-value is an advantage, as the heat loss path through the concrete block is longer, reducing cold bridging.”

great to be able to use their expertise, so the details are ones that they know work on site,” says Jeremy Dain. “The fact we all work together in the same office resembles the best aspects of design and build – everyone contributes to the process. Working closely with everyone makes the process much easier.” The finished house is a modest size, but the feel is spacious, and it would work well for a young family too. They might have built slightly smaller, but in order to ensure a home where they could stay even if they lost mobility, circulation spaces and bathrooms were sized to accommodate wheelchair use. There is also scope to convert a downstairs office to an en-suite bedroom, and space upstairs to accommodate long-term guests (they have had students living with them, for example) or overnight carers. In keeping with their wish to do right by the future, Bernard and Janet were keen to make the most of the south-facing roof and install a solar PV array – in fact, rather than use

Simple form The team kept the building form simple, though the clients opted for a small stepped out porch and study. Bernard and Janet preferred the appearance but this form was also driven by space constraints – in particular accommodating the lift that would assure them they could remain in their home for as long as possible. “It did mean we had to build a lean-to roof, which was harder to detail for airtightness, as the structure passed though the main airtightness layer,” Jeremy Dain explains. However for the most part, Greenheart already had a well-worked out set of details for their construction system, which meet passive house requirements for airtightness and lack of thermal bridging. “Greenheart are familiar with exactly what they are doing. It is really 1000

Total electrical energy usage (kWh)

was a big bonus. They were very keen to be cutting edge and remarkably open to learning. Terrifying clients really — always ahead of you! It made it a really enjoyable process.” Apart from some ground issues (the soil is impermeable, and shrinkable, clay) Jeremy Dain says the site was “a gift”. At Jeremy’s suggestion, an early decision was made to move the house to the back, north, edge of the plot, fitting the new house between the client’s old house to the east, and the Victorian terrace/semis to the west, and giving an ideal orientation for both passive solar gain and a good relationship with the garden, which would separate the house from the busy road. Greenheart use all the techniques of passive house whether or not a client is interested in certification. All their builds are highly airtight and designs “are usually run through PHPP just to check them over,” director Richard Hatfield says. They are also committed to low-impact materials and favour a timber framed I-beam construction, filled with cellulose and finished with a wood fibre board insulation and render system. “It’s a fairly easy way to build, and we have our own details, which our team are all familiar with, that we know perform in practice.” This build used a balloon frame (i.e. with a single wall rising through both storeys) so airtightness and insulation is continuous, and the first floor is hung off the walls. Insulation is at ceiling level, with a trussed roof above. “Airtightness is achieved by using ProPassiv board for racking – it also provides a vapour control layer, so it does three in one. The board is then taped to everything, we find this easier than taping to membrane which is flapping around.” Greenheart’s standard floor detail comprises a masonry plinth with an insulated inner leaf of lightweight block, with lightweight blocks supporting internal walls. “We use 300 mm EPS under the slab – it is cheaper, and the fact that it is thicker than

BRISTOL

800 600 400 200 0 -200 -400 -600

OCT

NOV

DEC

Electricity Demand

JAN

FEB

Solar Generation

MAR

APR

MAY

From Battery

JUN

JUL

From Grid

AUG

SEP

To Grid

above Graph showing total household electricity demand, solar PV generation, and energy exported to and imported from the electricity grid.

ph+ | bristol case study | 25


BRISTOL

CASE STUDY

CONSTRUCTION IN PROGRESS

1

2

3

4

5

6

7

8

9

1 Erection of the I-beam timber frame structure; 2 the PROPASSIV OSB provides airtightness and vapour control; 3 Pavatex Diffutherm wood fibre board fitted externally to the timber frame; 4 300 mm Warmcel insulation installed in the main loft. Thermal bridge reduction included: 5 mineral wool around & 6 PIR in front of steel I-beam, with 7 AAC lightweight concrete blocks at floor level and 8 PIR around the outside of the rooflight shaft; 9 60 mm XPS was installed at plinth level to protect wood fibre insulation boards from rain splash due to varying ground levels.

conventional roofing material on the south slope of the roof, an integrated PV roofing system covers the entire area, generating more than the house consumes (see ‘In detail’ for more). Heating and hot water are provided by a 4 kW Mitsubishi EcoDan CO2 refrigerant air source heat pump (a relatively new development, as most heat pumps on the market still contain hydrofluorocarbon (HFC) refrigerants). The improved performance of heat pumps, alongside the dramatic fall in the carbon content of grid electricity (as more renewables come on-stream, and coal power plants are retired) means that although fundamentally an electrically powered system, heat pumps now represent a fairly low carbon option – something that has changed even in the five years this project was in gestation. “I was always a huger resister of electric heating,” Jeremy Dain admits. “Electricity is a high-grade energy and heat is the lowestgrade form. But when you are using so little of it, as you do with a heat pump in a passive house, the picture changes.

26 | passivehouseplus.co.uk | issue 33

Piers Sadler explains the choice of a CO2 (officially known as R744) refrigerant heat pump. “Because of the slightly different physics of CO2 compared to HFCs, these pumps work more efficiently than conventional pumps at the higher temperatures needed for hot water. In contrast to a conventional house, in a passive house, as in an apartment, hot water is a relatively high proportion of the load. “But what I really like about it is that it uses CO2 and not a high GWP [global warming potential] refrigerant. HFC leakage over the unit lifetime can have a significant overall climate impact.” When Passive House Plus visited on an icy January morning, the house was wonderfully warm and inviting, the heated floor blissful beneath frozen toes. Underfloor heating is unquestionably a luxury — and in a less efficient envelope, it is also one of the easier ways to provide an unobtrusive, giant-sized heat emitter that will work well with a heat pump. In a passive house, as Jeremy Dain points

out, underfloor heating probably isn’t necessary. “Underfloor heating is lovely to have, but a passive house is so well insulated you can run the heating at the low temperatures that work well with a heat pump, even just with radiators.” And as Piers Sadler added, the radiators would not need to be very big – and would definitely be cheaper. Passive house powerhouse Bernard and Janet were keen to reduce the burden on the grid further, by using a battery to save some of their solar energy for use after dark, when grid load tends to rise. Although they are fairly expensive to buy, the calculations Piers Sadler carried out suggested that the battery (a Tesla Powerwall) would pay for itself in terms of fuel bill savings comfortably before its 20-year guarantee expired. When the shell of the house was complete, the passive house-friendly design and Greenheart’s meticulous construction meant that the airtightness level was an impressive 0.3 air changes per hour. It was clear that certification was going to be possible.


CASE STUDY

BRISTOL

SELECTED PROJECT DETAILS Architect: S2 Architects Contractor: Greenheart Sustainable Construction Civil & structural engineering: Element Structures Energy consultant: Piers Sadler Consulting Passive house certifier: WARM Building services contractor: Solarsense Airtightness tester: BAT Wall & roof insulation: Warmcel, via Greenheart Additional wall insulation: Natural Building Technologies Airtightness & vapour control board: MEDITE SMARTPLY Airtightness membrane: Ecological Building Systems Windows & doors: Rationel, via Greenmoose Roof windows: Fakro Heat pump: Mitsubishi Electric Ecodan, via Solarsense MVHR: Green Building Store (supply); Greenheart (install); Fourwalls (commissioning) Solar PV: Solarsense

Bernard and Janet consulted a few local estate agents about whether there was a value in doing so. “Most of them either didn’t know what we were talking about or doubted it would make any difference, but one did say that if they could get a certificate then that would be worthwhile.” The passive house ‘plus’ certification however came about more or less by accident. “We didn’t do anything in particular to achieve that standard, it really wasn’t on our radar,” Piers Sadler explains. “We were only thinking about achieving the performance for a classic passive house, and I was very much focused on the heat demand side.” (This tends to be the most demanding aspect of passive house with a modest-sized detached dwelling like this one). “But because the clients were keen on having the PV roof, and because heat pumps have such low primary energy demand, when the certifiers looked at our figures they told us that we had met the passive house plus standard anyway.” Bernard and Janet moved in a little over a year ago, and so far the house has certainly met their expectations. Although they are very keen to log all the data for the heat pump, PV roof and battery, the fact that manufacturers regularly update their software and change the way the data is saved and displayed is not always helpful, they say. Nonetheless, from the data they do have, the early indications are that in a mild winter (2018/2019) at least, the house uses even less heating than predicted in PHPP, and

total energy use is also comfortably below predictions. Now it is clear that the tiny upstairs radiators are never needed, the system is undergoing some fine-tuning, after which it should be possible to properly assess the heat pump’s co-efficient of performance, too. Based on the monitored performance so far, the building is comfortably meeting the operational energy target in the 2030 RIBA Climate Challenge, namely a primary energy total (including regulated and unregulated energy) of less than 35 kWh/m2/yr, a space heating demand of less than 20 kWh/ m2/yr, the absence of a fossil fuel boiler, and the offsetting of remaining emissions via contributing to UK renewable energy

projects (in this case, there was no need to offset, given the building’s net export of energy to the grid). The home’s simple form and clean white appearance sits comfortably among the mixture of styles and ages in the road. As Janet says: “So many of the passive house homes we saw doing our research were either social housing – which is great, but almost always quite small, and terraces or apartments, so not what we wanted – or they looked like they belonged on millionaire’s row.” “We are passionate about demonstrating how a normal, family home can really do the right thing for the environment, do the right thing for future generations. We really believe all homes should be like this.”

ph+ | bristol case study | 27


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CASE STUDY

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CASE STUDY

KEEPING IT MODEST

BRISTOL

Embodied Co2e: completion vs end-of-life

“Compared to what we see in many self-build designs, this build did not have very large spans: this is a huge advantage especially when you are building for high energy performance,” Richard Hatfield of Greenheart Construction explains. “When clients want big open plan living spaces or long runs of continuous floor to ceiling glazing, you end up having to put in big steels to support the span and get enough rigidity. And then you get thermal bridging issues. “We can insulate a steel [beam] enough to prevent any moisture risk, but you can’t match the insulation value of the rest of the wall, which means you need to increase the performance elsewhere, for example by making all the walls thicker. You face a similar situation if you have a lot of north-facing glazing.

“As the span gets larger, the steel has to get thicker, and with the biggest spans you can end up with a 300 mm deep beam – which can’t be accommodated within the thickness of a normal wall, meaning you then need to go to a non-standard structure to accommodate it – such as cantilevering floors out over the top of the steel. “Complicated and one-off details are always harder to achieve on site, because they are less familiar. Our team really know what they are doing with our standard details, but something non-standard requires more design time and more supervision, and therefore costs the client more.” While natural materials such as cellulose insulation and wood fibre board mean “significant cost uplift” over petrochemical foams, as Jeremy Dain explains, he adds that the simple form and modest finishes such as render, tile and timber cladding kept costs under control, as well as giving the house a fairly “normal” appearance.

650 600 550 500 450 400 Carbon Emitted kg CO2e/m2 NIA

One of the clients’ aims was to show others – including their local authority – that high-performing, eco-friendly housing need not look outrageous, nor cost an outrageous amount of time or money to build.

350 300 250 200 150 100 50 0 -50 -100 -150 -200

Cradle to practical completion

C: End of life

Mineral Wool

B: Use phase

Concrete

A4/A5: Transport/construction

Oil based

PV

Timber Based

Steel

WHERE DOES THE HOUSE’S ELECTRICITY COME FROM?

Cradle to grave

Composite

Inert Timber Plasterboard

EMBODIED CARBON

FROM BATTERY

37%

FROM GRID

31% SOLAR USED IN HOUSE

House electricity: 4,625 kWh Solar generated: 6,129 kWh From Powerwall: 1,705 kWh From Grid: 1,431 kWh To Grid: 2,668 kWh

32% This chart shows shows a neat split between solar generation used directly, energy drawn from solar power stored in the battery, and grid imports, from October 2018 to September 2019. From April to September last year, the house was almost completely (98%) self-sufficient in energy. Inevitably imports rise in winter, but even in the two coldest, darkest months, 20-25% of

the house’s total electricity was home-generated: in fact, in January 2020 the figure was a respectable 31%. There do appear to be storage losses, with the energy drawn from the battery apparently being 14% less than that put in. However, as with the heating performance of the house, these are preliminary figures only.

Builders Greenheart Construction commissioned Tim Martel, the creator of PHribbon, a PHPP-based tool which includes a life cycle assessment tool, to run the numbers. (For a fuller description of the methodology behind this calculation, see the embodied carbon box out in the Ruth Butler Architects passive house on page 38). The house has a total embodied carbon score up until practical completion stage of 338 kg CO2e/m2, disregarding sequestered CO2 in the timber and timber-based products. The cradle-to-grave figure works out at a net score of 437 kg CO2e/ m2, a figure which beats the 2025 target under the RIBA 2030 Climate Challenge. This figure includes the embodied energy for a large PV array, while ignoring the considerable operational carbon reduction this will generate. The figure would drop substantially if the timber and timberbased products avoided incineration at end of life.

Read more about this project in detail

ph+ | bristol case study | 29


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CASE STUDY

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ultraquietecodan.co.uk

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Domestic HVAC Product of the Year – Heating Units

30 | passivehouseplus.co.uk | issue 33

Search #ultraquietecodan


CASE STUDY

BRISTOL

WHAT IS A PASSIVE HOUSE ‘PLUS’?

A building certified to the passive house ‘plus’ standard not only drastically reduces energy use like a passive house ‘classic’, but it is also designed to produce as much energy on site as occupants consume. The energy generated must come from renewable sources and provide enough energy to operate the building throughout the whole year. It requires a minimum of 60 kWh/ yr of renewable energy generation for every square metre of the building’s footprint (as opposed to floor area), along with a maximum renewable primary energy (PER) demand of 45 kWh/m2/yr of floor area: this is the amount of electricity drawn from a theoretical future electricity grid which is powered 100% by renewables. The even more advanced passive house premium standard requires generation of 120 kWh/m2/yr and a maximum PER of 30 kWh/m2/yr. The targets for space heating demand (15 kWh/m2/yr) and heat load (10 W/m2) remain the same with all versions of the standard.

IN DETAIL Building type: 153 m2 detached, two-storey, timber frame house Location: Nailsea, Bristol, UK Completion date: July 2019

Ground floor: 225 mm concrete followed above by 300 mm PIR, 75 mm screed, 25 mm wood flooring. U-value: 0.074 W/m2K

Passive house certification: Certified passive house plus Space heating demand: 16 kWh/m2/yr Heat load: 10 W/m2 Primary energy renewable (PER) demand: 44 kWh/m2/yr Heat loss form factor: 3.17 Overheating fraction (PHPP): 4% (of time above 25C) Number of occupants: 2 Environmental assessment method: N/A Airtightness: 0.35 ACH @ 50 Pa Energy Performance Certificate: A (105) Measured energy consumption (Oct 2018 to Sept 2019): 4,625 kWh/yr measured TOTAL electrical consumption for 12 months, including space heating & hot water, according to Tesla Powerwall app. Divided by 153 m2 total floor area gives a figure of 30 kWh/m2/yr electrical consumption. Of this 1,312 kWh is used by the heat pump to provide space heating & hot water. Heat pump annual energy consumption:

Heat

DHW

Electricity (kWh)

705

607

Delivered Heat (kWh)

1,398

1,923

CoP

2.33

3.18

9

13

Delivered Heat (kWh/m /yr) 2

above The house’s plant room, and undercuts of circa 30 mm beneath internal doors to aid air circulation.

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings.

The digital magazine is available to subscribers on www.passivehouseplus.co.uk

clients paid a total £253.32 for grid electricity but received a £415.49 feed-in-tariff for exporting electricity to the grid, making a £162 profit on annual energy bills.

THERMAL BRIDGING External wall-floor: Lightweight concrete block at plinth level below inner chord of i-beam stud. Internal wall-floor: Lightweight concrete block; steel frame around double sliding door internal with Rockwool in timber frame on the outside; for SAP calculation ACDs used for thermal bridging. Energy bills: The house is all electric. Between 19/09/2018 & 02/09/2019 the

External walls: Baumit SilikonTop render with MC55 base coat (or cavity and larch rainscreen) externally, followed inside by 60 mm Pavatex Diffutherm, 300 mm I-beams insulated with Warmcel, 12 mm ProPassiv OSB, 25 mm services cavity, 15 mm plasterboard and skim. U-value: 0.11 W/m2K Trussed roof: GB-Sol roof integrated solar PV system to south roof; concrete tiles on breathable roofing membrane to north roof. 300 mm Warmcel on the flat, bridged by timbers at 10%, followed beneath by 12 mm ProPassiv OSB, 25 mm services cavity, 15 mm plasterboard and skim. U-value: 0.132 W/m2K Windows and external doors: Rationel Aura Plus solid timber with aluminium cladding, triple glazed, argon-filled low E. Average U-value circa 0.90 W/m2K. GBS Ultra sliding window, solid timber, triple glazed, argon-filled low E. Average installed U-value: 1 W/m2K Roof window: Fakro FTT U8 Thermo. Installed U-value 1.01W/m2K Heating system and hot water: Mitsubishi Ecodan QUHZ-W40VA /EHPT20Q-VM2EA air source heat pump and thermal store, supplying underfloor heating and radiators direct from the heat pump and domestic hot water from the thermal store. Heat pump uses CO2 as its refrigerant eliminating the risk of leakage of high global warming potential refrigerants through the life of the unit. Seasonal COP approx. 2.9. Thermal store standing heat loss 1.63 kWh/24hrs Ventilation: Passive house certified Paul Novus 300 MVHR, 93% efficient. Electricity: 7.23 kW roof integrated GB-Sol PV. Tesla Powerwall 13 kWh battery. Solar output in first year 6,129 kWh. Battery output in first year 1,705 kWh. Battery losses 17%. Green materials: Timber frame construction, Warmcel and Pavatex Diffutherm insulations.

ph+ | bristol case study | 31


HAMPSHIRE

CASE STUDY

C OAS T I N G HOME B E A U T I F U L LY D E S I G N E D H A M P S H I R E H O M E B R E E Z E S PA S T PA S S I V E S TA N D A R D

‘Architecture is the blissful moment when the site and brief come together,’ says architect Ruth Butler of the challenge she and her engineer husband faced in designing their family home, on a difficult urban site by the Hampshire coast. But it was a challenge they met and exceeded, because even though they hadn’t even planned to build a passive house, they soon realised the design was on course to meet the onerous energy standard anyway.

Words by David W Smith

32 32 | passivehouseplus.co.uk | issue 33


CASE STUDY

HAMPSHIRE

ENERGY BILL

£19

PER MONTH GAS BILL (see ‘In detail’ for more)

Building: 135 m2 detached timber frame house Location: Emsworth, Hampshire Standard: Passive house certified

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HAMPSHIRE

CASE STUDY

A

husband-and-wife design team comprising an engineer and an architect surpassed their original goal of creating a low energy new build near the Hampshire coastline when their home comfortably qualified for passive house certification. The joint expertise of architect Ruth Butler and engineer Julian Sutherland in sustainable design meant that their house required only a few tweaks to the original plan to get it over the line. In the end, they sailed past the passive house standard. And while Ruth calculated that building to the benchmark added 7.4% over building regulations onto the cost, it has proved life changing. Based out of her home office since 2015, Ruth has grown her architectural practice locally and designed three passive houses. Meanwhile, Julian qualified as a passive house designer through his work on the property. “We originally wrote ourselves a low energy brief focused on lots of insulation and airtightness, but we didn’t intend to build a passive house. Then when we tested it against passive house — not expecting it to be close — we realised if we put in more high-performing triple glazed windows, we could achieve it,” said Ruth. “As we no longer needed underfloor heating, we could spend that money on the windows.” The couple met while they were both working on the development of tennis court number one at Wimbledon in the mid-nineties. Over the years, in their respective careers, both Ruth and Julian have had a keen interest in low energy design. In London, they lived in a 1960s townhouse, but wanted to use their complimentary expertise to create a low energy house on the south coast. Ruth took charge of the design, while Julian did the passive house calculations. As an engineer in building services, he understood all about airtightness, insulation and ventilation. “The calculations showed it was outperforming expectations. But we actually did a lot of things over and above the passive house standard, such as using low embodied carbon materials and reducing water usage. We also avoided plastering all the walls,” he says. “Laying natural quarry tiles on the floors helped make it a dry building site and we used zero VOC [volatile organic compound] paint. I supervised the insulation to make sure there were no gaps or bad junctions, and we achieved 0.55 air changes.” The original desire to move out of London with their daughter — who is now 14 — to settle on the south coast was partly motivated by the family’s passion for sailing. Rather than travelling all the way out to the seaside and back to London at weekends, they wanted to live minutes from the sea. The couple bought a different site initially, but planning limitations spoiled their plans so they sold it on. They used the profit to fund the purchase of the brownfield site, in Emsworth, Hampshire, which was previously owned by St John’s Ambulance.

34 | passivehouseplus.co.uk | issue 33


CASE STUDY

G.01 F.01

HAMPSHIRE

Ruth took charge of the design, while Julian did the passive house calculations.

G.02

F.02

G.03 F.04

G.04 F.03

F.05

G.05

G.06

G.07

KEY

KEY

G.01 G.02 G.03 G.04 G.05 G.06 G.07

F.01 Bedroom F.02 Bedroom F.03 Bedroom F.04 Family Bathroom F.05 En Suite

GROUND FLOOR PLAN

FIRST FLOOR PLAN

ruth butler architects.com

0

2.5M mm

0

north

Photography: Peter Langdown Photography

ruth butler architects.com

Family Room Study Kitchen Dining Room Utility/Plant Room WC Living Room

2.5M mm north

There were many pros and a few cons. The pros were that the land was minutes on foot from Chichester harbour, the sailing club and shops. Julian could also commute to London from Havant station, a short bike ride away. The main challenge was designing a house that pacified the concerns of a dozen neighbours who had been infuriated by the plans of the previous owner. “Although the previous development had planning permission, it was insensitive and I would have hated it as much as them,” said Ruth. “It plonked a building in the middle and all the neighbours would have had a lot of overlooking and a big blank wall at the end of their garden.” Once Julian and Ruth had produced a more sympathetic design that didn’t overlook any neighbouring properties, their next task was to convince the neighbours. They put together a cardboard model that showed the view of the new property from each neighbouring house. “Once they all saw that, they were all on our side and consented. By the time we started building in 2014, they were all excited and feeding cake and cups of tea to the builders,” says Julian. With the neighbours onside, the local authority enthusiastically backed their proposals. But there remained challenges. First the land had to be cleared of rubble, oil contamination and asbestos from old hall and garage buildings on the site. The space itself, Ruth admitted, was “unprepossessing” and would not have appealed to everyone. It was narrow and surrounded on three sides by houses, but the awkwardness made it more affordable and there were lovely views south down a tree-lined lane. Rather than see the restrictions as a negative point, Ruth embraced the challenge of making the most of them. “As an architect, the more there are constraints, the better the solution needs to be. A difficult urban site gets your creative juices going more than a big empty field. Architecture is the blissful moment when the site and brief come together,” she says. Ruth designed an L-shaped 135 m2 detached home that slotted neatly into the long, thin area. The mass of the building was pushed

ph+ | hampshire case study | 35


HAMPSHIRE

CASE STUDY

We also took all the builders on a passive house-training course.

above Summer comfort is managed by a design which includes a fabric sail, and purge ventilation via roof windows which open and close automatically based on temperature and rain sensors.

to the northernmost side, so the outdoor spaces faced south. Using the L-shape allowed Ruth to design the house around four outdoor courtyards around the perimeter of the house. “The main south-facing enclosed courtyard garden is hidden from the many neighbouring properties. Then there are two smaller courtyards — one facing east and the other one west — that provide good light and ventilation to the back rooms. Finally, there’s an entrance courtyard that gives access from the lane and into the garage,” she says. For the interiors, Ruth wanted to move away from designing minimalist, plasterboard boxes with white walls. Instead, she decided to fill the house with natural materials. She used spruce CLT (cross laminated timber) panels for the entire superstructure, walls, floors and roof. The prefabricated panels provide a harmonious feel and, left exposed internally, an attractive finish. The panels allowed the house structure to be erected in four days and helped to make it airtight. To enhance their new home’s sense of style, Ruth and Julian used European oak bespoke joinery for the open tread staircase, recessed handrails, worktops and integrated shelves. For the floors, she chose quarry tiles that stand up to the demands of the family’s

36 | passivehouseplus.co.uk | issue 33

outdoor lifestyles. “When we’re drenched from falling out of our boats in Chichester harbour, we don’t want to worry about ruining the floors,” she said. The kitchen sits in the knuckle of the L at the heart of the ground floor. The living room and the dining room spin off down either side of the L shape. The ground floor has flexible spaces, including a family room that doubles as a fourth bedroom and a home office. Upstairs there are three bedrooms and two bathrooms. Outside, Ruth used Siberian larch rainscreen cladding because of its straight grain, uniform texture and durability. She says the untreated larch ages quickly to become silver, providing a maintenance-free finish that suits coastal living. Meanwhile, two wildflower meadow roofs enhance biodiversity and provide rainwater and irrigation. From Julian’s point of view the trickiest element of the build — as so often with passive houses – came at the outset when they had to track down contractors with sufficient knowledge. The most technically challenging task was to create the main ground-floor slab because of the insulation requirements underneath, he says. “Fortunately, the builder had good connections and we were pragmatic and patient. We waited until we found the right people before we set off and made no

snap decisions. We also took all the builders on a passive house-training course.” Julian says the build went smoothly and the couple had good oversight of the entire project. He visited about once a week, while Ruth transferred her office on site for the duration. Work began in September 2014 and was completed in May 2015, when they moved in. Julian describes the house as “sparkling, sunny, delightful and super-comfortable”. A hardy New Zealander, he now needs to take a pullover whenever he visits a friend not living in a passive house. The house won the 2017 Wood Award in the ‘private’ category. The judges were impressed by the “design, craftsmanship and attention to detail”. For Ruth, it became the perfect calling card for her new practice. “There is nothing better than bringing clients into the passive house and sitting them around the board-room table, which is also my dining room table. It makes a huge difference in winter and summer, when we have a big sailcloth that goes over the courtyard to keep the sunshine out of the house,” she said. “We use it to advocate for passive houses and we’ve had more than 100 visitors each of the past five years for the UK Passive House Open Days.”


CASE STUDY

HAMPSHIRE

CONSTRUCTION IN PROGRESS

1

2

3

4

5

6

SELECTED PROJECT DETAILS Client: Ruth Butler & Julian Sutherland Architect: Ruth Butler Architects M&E engineer: Cundall Ltd (Julian Sutherland) Civil & structural engineer: Price & Myers PH certifier: WARM Main contractor: Nicholas Coppin Ltd Heating & plumbing contractor: AD Boughton Ltd Electrical contractor: Johnson Electrical Airtightness tester: BRE Building system supplier: KLH UK Wall & floor insulation: Kingspan Thermal breaks: Compacfoam, via Green Building Store Green roof: Bauder Windows & doors: Internorm Roof lights: Vitral Sail shades: Solent Sail Shades Gas boiler: Viessmann MVHR: Paul Solar PV: BenQ Siberian larch cladding: Timbmet Ltd Low carbon cement (GGBS): Hansen Oak joinery: Nicholas Coppin Ltd Wool carpets: The Alternative Flooring Company Landscaping: John Brookes Landscape Design

1 The brownfield site, which was previously owned by St Johnâ&#x20AC;&#x2122;s Ambulance, before construction commenced; 2 the substructure which includes a hardcore followed above by sand blinding, and a damp-proof membrane; 3 visiting the Austrian factory where the cross laminated timber (CLT) structure was manufactured; 4 erection of the CLT frame was complete within four days; 5 construction of the wall build-up with airtight membrane and Kingspan Kooltherm insulation; 6 external walls are finished with Siberian Larch vertical rain screen cladding.

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings.

The digital magazine is available to subscribers on www.passivehouseplus.co.uk

ph+ | hampshire case study | 37


HAMPSHIRE

CASE STUDY

EMBODIED CARBON

STAGE A (cradle to practical completion), which includes emissions embodied in the materials (stages A1-A3), in transporting to the site and in the construction process itself (A4-A5). STAGE A-C (cradle to grave), which also counts any additional emissions that may be released in stage B – the usage stage, which includes repair, replacement, etc and emissions from the building’s energy and water use (excluded in this case, as per the RIBA 2030 Climate Challenge) – and stage C, the end of the building’s life. Where bars are less than zero it represents storage of CO2 in timber and timber-based products. It is only in the worst default case that these are re-released into the atmosphere by incineration. There is great potential for improvement here (in stage D) if the building can be disassembled and reused or recycled into something more meaningful than woodchip. Excess solar energy from the PV array that is exported into the grid isn’t counted in these figures. RICS recommend it be included in stage D, which includes the potential environmental benefits or burdens of materials and components beyond the life of the project, as well as emissions reductions from microgeneration fed into the grid. It’s important to emphasize timing. The stage A emissions have already occurred in delivering a completed building. The stage B emissions are an estimate for the assumed 60-year life (as per RICS) of the building’s use, such as eventual replacement of mechanical plant, windows, cladding, etc, but in reality the stage C emissions may not be an issue for well over 100 years. Even in the use stage, some of these estimated emissions may not occur for, say, 50 or more years, and some may be prevented – for instance if CO2 sequestering products are reused or recycled after being removed. Similarly the stage C emissions include assumptions (based on RICS reliance on current construction and demoltion waste statistics in the UK) that 75% of timber removed from buildings will be incinerated and 25% landfilled. But by the time buildings being designed today reach their end of life, it seems reasonable to assume the releasing of sequestered CO2 emissions may be heavily restricted.

38 | passivehouseplus.co.uk | issue 33

Embodied Co2e: completion vs end-of-life

kg CO2e/m2 NIA

Carbon Emitted >

600

400

200

0 < Carbon Stored

While this house is extraordinarily green in terms of its miniscule operational energy use, how does it fare in terms of the CO2 embodied in the building itself? Does it meet the targets set out in the RIBA 2030 Climate Challenge? PHribbon, a new PHPP-based tool, makes it relatively simply to estimate embodied carbon of buildings designed in the software. Ruth Butler commissioned Tim Martel, the creator of PHribbon, to run the numbers. The figures are expressed in terms of CO2 equivalent (emissions of CO2 and other greenhouse gases converted into the equivalent amount of CO2) and take account of the vast bulk of the building materials, as well as estimates for emissions in transport and the construction process itself. The figures are presented here in terms of kg CO2e per m2 of net internal area, as this is the method selected by The Royal Institution of Chartered Surveyors (RICS) and referenced in the RIBA 2030 Climate Challenge. The graph includes two bars – to emphasize the difference between emissions up to the point of practical completion, and total cradle-to-grave emissions. Materials are divided into different groups (eg oil-based products including oil-based insulation, EPDM roof membrane, flooring; inert products including plaster and concrete roof tiles, etc). The two separate bars include:

C: End of life B: Use phase A4/A5: Transport/construction PV

-200

Plasterboard Windows Concrete Brick

-400

Oil based

Cradle to practical completion

Cradle to grave

Timber

Design and construction quality is also an important factor. There is evidence to suggest that passive houses offer a durability benefit – such as the 25th anniversary analysis of the first passive house, in Darmstadt, which found the building’s fabric and ventilation system in a remarkably good condition, and even concluded that the building’s experimental triple glazed units had not lost performance, but may need the glazing replaced in another 25 years. When the apparent durability and robustness of passive houses is combined with the architectural quality of this house, it seems reasonable to expect such a home to endure for far longer than a typical build – even without considering how the exponentially growing and converging climate and resource use crises are bound to force the hands of future generations to maintain and upgrade existing stock rather than building afresh. In this case, the house has a total embodied carbon score up until practical completion stage of 286 kg CO2e/ m2, disregarding sequestered CO2 in the timber and timberbased products. The cradle-to-grave figures work out at a net figure of 290 kg CO2e/m2, meaning that the building passes the embodied carbon target of 300 kg CO2e/m2 in the 2030 RIBA Climate Challenge. That figure would drop further if the structure was salvaged at end of life – a plausible assumption, given that studies estimate that up to 80% of a given CLT structure may be reusable once buildings are deconstructed. Reuse and recycling benefits would be accounted for in a stage D, which is zero in the current scenario.

Read more about this project in detail


CASE STUDY

HAMPSHIRE

IN DETAIL Building type: Detached family home, 134 m2 (treated floor area) or 150 m2 (GIA), factory-built cross laminate timber frame Location: Emsworth, Hampshire, UK Completion date: May 2015 Budget: Not disclosed Passive house certification: Passive house certified Space heating demand (PHPP): 8 kWh/m2/yr Heat load (PHPP): 10 W/m2 Primary energy demand (PHPP): 96 kWh/m2/yr Heat loss form factor (PHPP): 1.5 Overheating (PHPP): 1.7% of year above 25C Number of occupants: 4 Airtightness (at 50 Pascals): 0.55 ACH Energy performance certificate (EPC): N/A MEASURED ENERGY CONSUMPTION (Dec 2018 to Nov 2019) Total household grid electricity consumption: 5,598 kWh / 42 kWh per m2 Total gas consumption (space heating + hot water): 3,461 kWh / 26 kWh per m2 Total solar thermal produced: 1,197 kWh Total PV consumed (by household + electric vehicle): 980 kWh Total PV exported to grid: 444 kWh Total electric car electricity use (from grid + PV): 3,022 kWh Thermal bridging: Average thermal bridge

0.01 W/mK Energy bills (estimated): Estimated annual electricity bill of £1,132 per year for household use (not including electric car charging) based on a unit price of 17.33p per kWh, 29.59p per day standing charge & 5% rate of VAT (uswitch.com). Estimated annual gas bill of £230 (or £19 per month), based on a unit price of 3.640p per kWh, standing charge of 25.44p/day, and a 5% VAT rate. The household also receives a renewable feed-in tariff of approx. £120 per year, making for a net total household energy bill of £1,242 (not including car charging), or £104 per month. Note this use also includes the running of Ruth Butler’s home office. Ground floor: Hardcore followed above by sand blinding, RIW Shetseal 226 DPM, 250 mm Kingspan Kooltherm K3 insulation (laid break-bonded), 250 mm Foamglas T4+ between slab toe and footings, 150 mm concrete slab w GGBS float-finished, 10 mm floor finishes. U-value: 0.079 W/m2K Walls: Factory-built 94 mm cross laminated timber structure exposed internally, followed outside by IKO Rubershield-Light breather membrane, two layers of 140 mm Kingspan Kooltherm insulation boards, laid horizontally and vertically between 140x50 mm pre-treated timber battens, followed outside by 15 mm OSB3 T&G board, Pro Clima Solitex Fronta WA membrane (joints taped with Tescon INVIS), 25x25 mm vertical and horizontal timber battens, 44x20 mm Siberian Larch vertical rain screen cladding. U-value: 0.081 W/m2K Roof: Bauder wildflower blanket followed underneath by 100 mm extensive substrate, filter fleece, 40 mm drainage board, protection fleece, root resistant capping

sheet, underlay, 100 mm (average) PUR insulation to fall, vapour barrier, factory-built 140 mm cross laminate timber structure (exposed internally). U-value: 0.12 W/m2K Windows & external doors: Internorm HF310 aluminium/timber composite triple glazed windows and Internorm HS330 Lift-and-Slide doors. U-value: 0.69 W/m2K. RK entrance door. U-value: 0.72 W/m2K Roof windows: Vitral A98 thermally broken PPC aluminium framed and triple glazed panels (super low-E inner with Argon filled cavity), opening panels operated via Windowmaster actuator with temperature and rain sensors. U-value: 0.79 W/m2K Heating system: Gas-fired condensing Viessmann Vitodens 242F boiler with integral domestic hot water cylinder and solar thermal pump, 3 m2 roof mounted solar thermal panel Viessman Vitosol 200T which produced 1,197 kWh (9 kWh/m2) from Dec 2018 to Nov 2019. Ventilation: Paul Novus 300 whole house heat recovery ventilation unit (PHI certified heat recovery efficiency 91%). Electricity: 5 no. BenQ 330W solar panels with 1.65 kW installed capacity. Produced 1,424 kWh from Dec 2018 to Nov 2019, of which 444 kWh was exported to the grid, leaving 980 kWh for general household electricity consumption. Other green features: Brownfield site, within walking distance of town centre with shops & amenities. Existing buildings on site were recycled and re-used (e.g. bricks into hardcore, two 6 m long steels reused), VOC-free interior finishes (e.g. quarry tiles & undyed carpets, VOC-free paint by Lakeland Paints), EV charging point.

Energy Use & Generation

ELECTRICIT Y U S E

Oct 2019

GAS U SE

Sep 2019

SOLA R THE R MAL

P V GENERATI ON

Aug 2019 Jul 2019 Jun 2019 May 2019 Apr 2019 Mar 2019 Feb 2019 Jan 2019 Dec 2018

-1000

-500

0

Energy flow kWh

500

1000

1500

ph+ | hampshire case study | 39


DUBLIN CITY

CASE STUDY

ENERGY BILL FROM

€34

PER MONTH (all space heating,

ventilation, hot water, lighting, fans, pumps etc but excluding plug loads) Building: Extensive refurbishment & extension of Victorian mid-terrace, 115 m2 Location: Dublin 8 Budget: €280,000 Standard: A1 BER rating & NZEB

V I C TO R I A FA L L S

19TH CENTURY HOME DROPS ENERGY DEMAND BY 94% This ambitious renovation and extension of a single-storey Dublin redbrick, bringing it up to an A1 rating while far exceeding the new build NZEB standard, provides a beautifully-detailed blueprint for delivering warmth, comfort, and healthy indoor air — as well as extra space and living density — in historic city centre properties.

Words by John Cradden

40 40 | passivehouseplus.co.uk | issue 33


CASE STUDY

DUBLIN CITY

ph+ | dublin city case study | 41 41


DUBLIN CITY

CASE STUDY

T

his Victorian mid-terrace redbrick house in Dublin 8 underwent a stunning renovation and extension that was completed last year, but a near ten-year hiatus between planning permission and construction also allowed its architect to use it as a highly insightful case study in retrofitting older dwellings to the nearly zero energy building (NZEB) standard. Owner Fiona Whelan had bought the 92 m2, single-storey house in the early 2000s and commissioned architect Daniel Coyle to draw up plans to tear down the existing, small extension (built in the 1980s) and replace it with something altogether more comprehensive, with a reconfigured layout incorporating two bedrooms, two bathrooms, and open plan living / kitchen / dining areas. The emphasis was on creating flexible and adaptable spaces, and the ability to close off or open up rooms. The design and planning permission was granted in late 2008, but just as the boom was clearly turning to bust “we just parked it for a few years and, financially and everything, we just decided to live in the house as it was”, says Whelan. She had forged her connection with Coyle through a project that he completed for

42 | passivehouseplus.co.uk | issue 33

her parents a few years previously, and they remained in touch. By the time they re-engaged in 2017, Coyle had developed expertise in energy efficient building design, having completed — with distinction — a master’s degree in energy retrofit technology at DIT (now TU Dublin) in 2015. He now lectures part-time on the college’s MSc in building performance. Armed with this knowledge, Coyle was able to bring Whelan on board with modifications to the original 2008 design to help achieve the NZEB standard, and an A1 energy rating. “It’s probably very fortuitous, in a way, that there was that delay because if it had been built in 2008, it probably would not have achieved such a high energy performance target,” says Coyle. In fairness, the original brief did include a stipulation that the dwelling be transformed into a “future-proofed low energy home”, but he admits there were no specific discussions on the way to achieve this, or whether it could have been done to passive house or any other standard. “These standards were less defined at the time, and perhaps we saw them then as too ambitious or difficult to achieve in a retrofit project.” Among the more significant tweaks to the


CASE STUDY

DUBLIN CITY

It’s great to be able to combine a low energy house with an attractive design.

original design were to the roof and facades of the extension, so as to achieve a better balance between winter time solar gain and summer time shading, along with ambitious fabric insulation standards, airtightness, low energy heating and ventilation strategies. The old roof was a mono-pitched design, in a way that would have resulted in excessive glass on the south facade of the extension, so this was replaced by a barrel-vaulted roof with a sun-shading canopy. “We kind of realised that with a bit more knowledge and knowing that there was too much glass might expose it to the risks of overheating,” says Coyle. The ten-year hiatus was clearly fortuitous for another reason, as the roof is by some way the most striking design feature of the whole dwelling. Although Coyle can’t recall if it was deliberate, there is a nice aesthetic synchronicity between the upper barrelvault shaped windows at both ends of the

Photography: Myles Shelly & Patrick McKenna

extension with the arches of the old hallway and the front porch on the outside. For Whelan, any kind of renovation would have been an improvement on what was a very dark, cold building with little connection to the southwest-facing garden, and which was very much at the end of its lifecycle in terms of the roof finishes, interior, windows, and services. Aside from the poorly designed original extension and a problematic layout, “my biggest problem with the house was that it wasn’t working from a heating point of view,” says Whelan. “It was freezing; just damp, dark and miserable, “adding that they were spending on average €200 to €250 per month just to try to keep the place warm. So, they were clearly receptive to new and better ways of making the renovated home as warm, comfortable and energy efficient as possible. By 2017, Whelan had accumulated a

decent budget and Coyle had garnered more than enough knowledge in deep retrofits, and so they began the process of re-designing and tendering in September of that year, with construction beginning the following month. The extension and much of the back half of the original house was demolished and rebuilt and a much larger extension — spanning the length of one side of the large garden — was built, pushing the total footprint to 115 m2. With contractor Dave Thompson of DP Building and Carpentry at the helm, the build went smoothly, despite Thompson not having a huge amount of experience in building to this standard of energy efficiency. “It wasn’t a contractor who had done passive houses or airtightness before so, as always, I thought that would be more of a challenge, if you didn’t have someone with previous experience, but actually he took it all on board very well,” says Coyle. Dave Thompson likewise praised Coyle’s design skills, while singling out mechanical contractors Green House too, who he said “were excellent”. What also helped were clients who had the budget and were pretty much on board all the way. “It wasn’t a project where we had to penny-pinch or cut corners, or you’re trying to explain or argue the case for a particular amount of insulation or something. I mean, that was quite easy in a way in that they were behind everything; they did appreciate [the idea of] investing in the fabric to get to a high energy standard.” As well as the fabric upgrades, Coyle also specified – in line with NZEB and passive house design principles – triple glazing, high levels of airtightness, an exhaust air heat pump and solar PV, not to mention passive solar gain strategies and the elimination of thermal bridges. But rather than use passive house modelling tools (PHPP) to come up with the appropriate mix of measures, Coyle used DEAP, Ireland’s standard building energy rating and Part L assessment tool. “Although I had done some training in PHPP and have a fairly good understanding of passive house design principles, I am not a certified passive house designer. I have much better working knowledge of DEAP as a design tool.” Furthermore, he adds that although perhaps less rigorous, it’s a far simpler tool for the calculation of energy performance and negated the need for an external passive house consultant and the costs associated

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DUBLIN CITY

CASE STUDY

CONSTRUCTION IN PROGRESS

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1 The extensive refurbishment underway of the mid-terrace Victorian house; 2 the existing, small rear extension was demolished, and replaced with a new extension spanning the length of one side of the large garden; 3 stainless steel angle support brackets for sliding doors / glazed screens, bolted to the edge of the floor slab, with 150 XPS insulation below DPC level; 4 underfloor heating was installed throughout the house, above the Xtratherm PIR insulation; 5 the extension walls feature 200 mm KORE EPS as part of a Webertherm EWI system, on 215 mm Roadstone Thermal Liteblock concrete blockwork; 6 the new pitched roof, with Intello membrane and Velux top-hung triple glazed roof windows; 7 Remmers iQ-Therm capillary-active internal insulation; 8 the solar PV array feeds directly into the house’s general electricity supply, with any excess electricity being first diverted to the heat pump for hot water production; 9 brickwork on the front facade repointed with lime mortar.

with that. “And at the end of the day DEAP, and the BER rating system, is the de-facto compliance tool for new build and major renovations in Ireland, so this gives it a certain advantage.” He does say, though, that if he was approaching it again, he would consider going for passive house certification. By the end of the stripping out and demolition, there wasn’t that much left of the original fabric of the house besides the front two rooms and adjoining hallway. The solid brick front walls had to be repointed with

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lime, but some of the existing plaster was simply repaired, because it provides a good level of inherent airtightness, before being dry lined internally. Insulating walls internally always presents a moisture risk, because it can create a ‘dew point’ for condensation between the old wall and the new insulation, but there is also an extra risk with old brickwork, because it is quite porous to rain coming through from the outside. To mitigate this risk, Coyle specified Remmers iQ-Therm internal insulation, a

capillary-active, diffusion open and breathable PUR foam insulation board designed for use on conservation projects, which should enable the wall to dry out internally. There is also a lime parge coat to the inside face of the brick wall, and lime plaster on the inside of the iQ-Therm too (lime is more breathable than traditional cement), while the base of the walls were injected with a rising damp barrier. Coyle did not undertake a condensation risk analysis, but feels that given the limited area and height of the wall, the


CASE STUDY

DUBLIN CITY

above 3D floor plan of the finished dwelling, with bedrooms in the original part of the dwelling (at right) and kitchen and dining areas in the new extension (at left); below graphic sequence showing demolition of the old extension and construction of the new one.

overhanging eaves, its sheltered aspect, the sunny south-east orientation (which will help the wall to dry out), and the modest U-value achieved by internal insulation (0.32), the risk of condensation and damp is low. A cost effective retrofit? Another point of interest here is that Coyle was able to use this house as a case study in extrapolating from the overall budget the specific costs of the fabric and systems upgrades required to deliver an A1 energy rating, which he estimated at €60,000 of the total budget of €280,000 (or €75,000 if you include VAT and fees). Coyle also estimated the annual savings in

energy costs at some €4,000 a year. It’s important to note these figures are the cost of upgrading this house from a theoretical BER rating of G right up to A1. In other words, this is comparing the finished and remodelled A1-rated house, including the extension, with the exact same design and layout but “reverse-engineered” with no energy efficiency measures at all. In practical terms this means no insulation, very poor airtightness, single glazed windows, a non-condensing gas boiler (70% efficiency) without controls and no ventilation – other than via infiltration. It also assumes that the occupants would have fully heated the G rated house, rather than that simply made do with

colder indoor temperatures, so it is most likely an overestimate. In reality, of course, any extension built in 2017 would legally had to have met the 2011 version of Part L of the building regulations, so the ‘extra over’ capital cost would be the difference between achieving that standard and an A1 rating, rather than the difference between getting a G and an A1. So, the real ‘extra over’ cost of going to A1 versus meeting minimum requirements would be significantly less, but the savings on energy bills would be less, too. “If you are asking the question of whether a deep retrofit such as this is cost-effective, or a good financial investment, then really you need to do a proper life cycle cost calculation and investment appraisal, as opposed to just a simple payback calculation — which [in this case] would be 19 years — says Coyle. “This would mean taking into account fuel inflation, interest rates etc and over a 30-year plus investment time frame.” But even this is without considering ‘co-benefits’ such as reduced healthcare costs from living in a warmer, more comfortable home with good indoor air quality. Coyle also monitored the energy usage costs over the first 12 months of residency, which worked out at €480 for space heating, hot water, ventilation and lighting, but not including plug loads (see the ‘In detail’ panel for more). This is some €120 more than the DEAP estimate, but he says this gap can be explained by commissioning issues with some services, including adjustments to thermostat and

ph+ | dublin city case study | 45


DUBLIN CITY

CASE STUDY

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46 | passivehouseplus.co.uk | issue 33

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CASE STUDY

heat pump settings, and some drying out of the wet plastering, but also the discovery that the building’s large solar PV array was not working for the first three months. The array feeds now directly into the house’s general electricity supply, with any excess electricity being first diverted to the heat pump for hot water production. Fiona Whelan says that when she moved back in May 2018, the underfloor heating was never turned on all the way into the winter of that year. “I kind of did think around December time when I didn’t feel any kind of heat underfoot, was this even working? Anyway, we carried on through the winter and then we were told the thermostats were incorrect, and so there was actually no heating, but because the house was so insulated it actually wasn’t too bad. You know, we didn’t feel the lack of it.” The project was not grant-funded, as SEAI’s PV and heat pump grants were not available at the time, and Coyle did not think it would qualify for external wall insulation grants. SEAI’s deep retrofit scheme was also just getting off the ground in 2017, so if it was being undertaken today, there would be significantly better financial support available for a retrofit like this. It’s worth noting that Coyle didn’t specify a full mechanical ventilation with heat recovery (MVHR) system, but rather an exhaust air heat pump solution from NIBE, which he described as a hybrid of MVHR, demand-controlled ventilation (DCV), and an air source heat pump, which he says is ideal for a small but very thermally efficient

and airtight house. The exhaust air system also requires no outdoor unit, making it ideal for retrofitting in small, urban gardens. Overall, the house scores impressive marks for sustainability: it reuses an existing historic structure, is modestly sized, and right in the middle of an urban centre. And it successfully reconciled the conflict between respecting the original building’s architectural value and producing a contemporary home, all while achieving near perfection in energy performance terms. Coyle is particularly pleased that the renovated house is performing as an ultra-low energy home, but also remains a nice place to be. “It’s great to be able to combine a low energy house with an attractive design, because sometimes you can feel like the passive or the low energy aspects of a house can be at the expense of the things that make it a nice, functioning space.” With all this, it’s no surprise to hear how

DUBLIN CITY

much Fiona Whelan loves their home now, particularly the warmth and the connection to the garden. “I absolutely just love getting home and to just sit there at the back and look at the garden come rain hail or shine, because it’s floor-to-ceiling glass and it’s kind of in the garden, and it’s just magic. I don’t know what to say, except I’m just the luckiest person in the world.”

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings.

The digital magazine is available to subscribers on www.passivehouseplus.co.uk

SELECTED PROJECT DETAILS Client: Fiona Whelan Architect: Daniel Coyle Architects Civil engineer: Lohan & Donnelly Engineers Project management: Daniel Coyle Architects Main contractor: DP Building & Carpentry Quantity surveyor: Modia Consulting Mechanical contractor: Green House Electrical contractor: Niall Lynch Electrical Services Airtightness tester: Evolved Energy EPS insulation: KORE Internal insulation: Remmers, via Conservation Technology Mineral wool insulation: Rockwool PIR insulation: Xtratherm Airtightness products: Ecological Building Systems Alu-clad windows & doors: Vindr VS Timber sash windows: McNally Joinery Interior fit-out: Wabi-Sabi Concrete polishing: P-Mac Heat pump: Unipipe, via Green House Solar PV: Green House Wood burning stove: Morso, via The Stove Depot

Read more about this project in detail

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DUBLIN CITY

CASE STUDY

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48 | passivehouseplus.co.uk | issue 33

Book your place today! To book your place, or to find out more details, visit www.aecb.net/carbonlite/ carbonlite-retrofit-training-course the Association for Environment Conscious Building AECB, PO Box 32, Llandysul, UK SA44 5ZA t: 0845 456 9773 e: membership@aecb.net


CASE STUDY

DUBLIN CITY

IN DETAIL Building type: Mid-terrace Victorian house dating from c. 1890. Comprehensively refurbished with new single-storey rear extension, total floor area 115 m2. Location: Dublin 8 Budget: €280,000 (excluding VAT, interior fit-out, garden works & professional fees). Completion date: April 2018 Passive house certification: None, PHPP analysis not carried out INDICATIVE BER Before: F BER (433 kWh/m2/yr) After: A1 BER (24 kWh/m2/yr) MEASURED ENERGY CONSUMPTION Before: N/A After: Total annual measured energy consumption for first year of occupancy was 5,048 kWh (this is an all-electric house). But this total includes an estimated 3,050 kWh of appliances / plug-loads (calculated using PHPP electricity worksheet). Balance of energy consumption for all heating, hot water, ventilation, fixed lighting and auxiliary loads (fans, pumps etc.) is therefore 1,998 kWh. Equates to 17 kWh/m2/yr. Based on 1 year’s utility bills actual consumption (April 2018-April 2019). ENERGY BILLS: Before: N/A After: €480 including VAT (April 2018-April 2019) electricity costs for heating, DHW, ventilation, auxiliary and fixed lighting (excludes plug-loads), or €40 per month. Dual rate meter installed. However, Daniel Coyle expects this will reduce to €30 per month now that PV & thermostat issues have been sorted out. Fiona Whelan also estimates that she spends €50 per year on wood for her stove (€4 pm). AIRTIGHTNESS (AT 50 PASCALS) Before: N/A

After: 1.8 m3/hr/m2 at 50 Pa Thermal bridging: Combination of calculated Psi-values and ACDs used. Calculated Y-value of 0.04.
 GROUND FLOOR: Before: Uninsulated concrete floor U-value: 0.42 W/m2K After New concrete floor (exposed polished concrete floor) insulated with 150 mm Xtratherm PIR insulation. U-value: 0.10 W/m2K WALLS Before: Solid brick / block walls with no insulation. U-value: 1.76 W/m2K After: 230 mm brickwork (repointed with lime mortar), lime plaster, 80 mm iQ-Therm insulation, 15 mm lime plaster finishes. U-value: 0.32 W/m2K ROOF Before: Sloped with mineral wool insulation. Roof slates to sloped areas and torch on felt to flat roof areas externally. 50 mm mineral wool insulation on the flat between roof joists, plasterboard ceiling internally. U-value: 0.67 W/m2K New pitched roof: Slates, on wind-tight layer, 220 mm mineral wool between joists, Intello Plus, 62.5 mm Xtratherm PIR. U-value: 0.12 W/m2K EXTENSION Extension floor: New concrete floor (exposed polished concrete floor) insulated with 150 mm Xtratherm PIR insulation. U-value: 0.10 W/m2K Extension walls: Webertherm EWI system: 15 mm acrylic render, on 200 mm EPS (graphite), on 215 mm Roadstone Thermal Liteblock concrete blockwork, on 12 mm sand-cement plaster parging (airtight layer), on 50 mm Rockwool MW insulation, on plasterboard and skim U-value: 0.12 W/m2K. XPS below DPC level. 50 mm Xtratherm insulation on the upstands and at window reveals.

Extension roof: Zinc standing seam roofing, on plywood, on 50x35 mm battens/counter battens, followed underneath by breathable roofing underlay, 250 mm timber joists fully filled with mineral wool insulation, Intello Plus airtight membrane / VCL, 50 mm insulated service cavity (mineral wool), 12.5 mm plasterboard ceiling. U-value: 0.13 W/m2K WINDOWS & DOORS Before: Single glazed, timber windows and doors. Overall approximate U-value: 3.50 W/m2K New triple glazed windows: Alumil aluminium glazed screens / sliding doors, with thermally broken frames (outer frames embedded in EWI layer), triple glazed (low-e, soft-coat, argon gas filled units, Ug=0.6 W/m2K). Overall average Uw value of 0.85 W/m2K Roof windows: Velux top-hung triple glazed roof windows. Overall U-value: 1.1 W/m2K HEATING SYSTEM Before: +15-year-old gas boiler & radiators throughout entire building. After: NIBE F730 whole house extract ventilation / exhaust air heat pump. Space heating efficiency: 354%, domestic hot water efficiency: 206% (Ecodesign Data). Underfloor heating throughout house (and two bathroom towel radiators). Secondary / back-up heating provided by Morso 5660 wood-burning stove, with external air supply for combustion, 88% efficiency. VENTILATION Before: No ventilation system. Reliant on infiltration, chimney and opening of windows for air changes. After: NIBE F730 whole house extract ventilation / exhaust air heat pump. Electricity: 12 m2 (8 panels) solar photovoltaic array with average annual output of 2 kW.

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WEST IRELAND

CASE STUDY

DOUBLE S TA N DA R D S M AYO H O M E TA K E S PA S S I V E A P P R O A C H T O N Z E B

Sited on the side of a hill in the west of Ireland, a new home that meets the NZEB and passive house standards boasts a locally-made and super-insulated timber frame, and is designed to fold cleverly into the rural landscape.

Words by John Cradden

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CASE STUDY

WEST IRELAND

ENERGY BILL

â&#x201A;¬100 PER MONTH

for all energy during winter

Building: 276 m2 detached timber frame house Location: Castlebar, Co Mayo Standard: Uncertified passive house / NZEB BER: A2

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WEST IRELAND

CASE STUDY

A

s design briefs go, it can sometimes be a bit of a jump in the dark: how do you build a contemporary house on a prominent hill in an Irish rural location that blends seamlessly enough into the landscape? This distinctive but visually sensitive detached passive house is located in an area where the local council encourages “high-quality, contemporary-style house design”, but its owners and architect had to change the location and replace the original design with a completely new one to get planning permission. But in doing so the owners also took the opportunity to switch from a block-built construction to a prefabricated timber frame, and while this required further revisions and calculations, the final result is arguably a better performing and greener home. Michelle Duffy and Dave Monaghan approached architect Mark Stephens back in 2015 looking for a design for a new home on a large, family-owned site near Castlebar, Co Mayo. Stephens came up with a compact, single-form, two-storey elongated design that was located fairly high up on what was an exposed and elevated site. The couple were keen on having an upside-down layout,

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with living spaces on the top floor, to take advantage of the views. But as far as the council planners were concerned, this wasn’t going to work as one of their design guidelines is that you can’t have houses on the very tops of hills. “It’s rare the planners would kick up such a fuss, but their site is really elevated,” says Stephens. So they moved the house down to a lower position and in doing so changed the design to an offset, stepped-out layout that, among other things, would maximise solar gain as well as break down the mass of the dwelling into smaller forms, including the creation of a separate, single-storey bedroom zone independent to a two-storey living area. The couple also adopted the council’s recommendation for a “low pitched copper or zinc roof with extended eaves, combined with natural materials and glass to create a low impact design”. The very low-angled, diagonally pitched roof, designed in a sculpted, origami folding style, works brilliantly against the sharp angles of the rest of the house, while managing to be visually subtle and low-impact. “Traditionally, you’d have a traditional gable and a normal pitched roof, but to keep


CASE STUDY

WEST IRELAND

I think the level of commitment from the builders is visible.

it low and flat, the pitch is actually on the diagonal. So, you’re diagonalizing the pitch and it’s more of a sculpted design,” Stephens says. Duffy and Monaghan also considered a grass roof to help the house blend into the hillside, but it was cost-prohibitive, so they opted for a metal-effect membrane in the end. “It ties in with a number of local agricultural roofs nearby,” says Duffy. The couple also wanted to build to passive house standard for a variety of reasons, including environmental, long-term running costs and a family connection to the sustainable energy industry (Monaghan’s father owns a geothermal heat pump business). But while this was diligently adhered to throughout the process from design to completion through modelling in PHPP, the passive house design software, they chose not to go the certification route for reasons of cost, as well as the imminent arrival of a new baby. The switch from the initial block-build structure to a timber frame was driven by discovery that for the new and more complex design, a masonry build would work out more expensive. “The timber frame came about due to the design. The masonry build was working out more expensive, as those we approached felt the design was complex,” says Duffy. “We were really impressed by Long Life Structures (LLS) when we met them, and it grew from there. We are not in the construction industry ourselves and we both worked full-time so wanted an uncomplicated build method. LLS ticked all the right boxes and were not fazed by the design.” Architect Mark Stephens says that part of the attraction of Long Life Structures was their package, which included a lot of the heavy lifting, the skilled trades and co-ordination onsite. “From a construction point

Photography: Kelvin Gillmor

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WEST IRELAND

CASE STUDY

CONSTRUCTION IN PROGRESS

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The construction of the house in sequence including; 1 insulated raft foundation with 200 mm EPS insulation; 2 the first storey of the timber frame system; 3 erection of I-beams for the intermediate floor; 4 the second storey walls, which would later be filled with cellulose insulation; 5 timber structure of the sculpted, origami-inspired roof; 6 pro clima Solitex Plus breather membrane being installed on the roof; 7 battening over the membrane to form a ventilated cavity; 8 installation of the Alkor PVC roof; 9 drone shot of the the finished roof.

of view the timber frame was a lot easier to build once everything was calculated. The only blockwork that was required was the external leaf and if we had to build two leafs there would have been a tricky proposition to build; especially the sloping wall plates and with each rafter being specifically, individually cut.” But above all, it made sense for a more energy efficient house, Stephens says. “The timber frame makes a big difference in performance… It was a lot easier to ensure airtightness early whereas the house is practically finished by the time

54 | passivehouseplus.co.uk | issue 33

you are able to test airtightness on a cavity wall-built house.” Galway-based Long Life Structures specialises in prefabricated high quality factory built systems. They use natural materials (cellulose and sheep wool insulations were used here) and sources its timber mostly from northern Europe, Austria and Russia. According to founder Emmet Nee, all of the 60-odd projects it has been involved with to date in Ireland have been below 0.6 air changes per hour on their airtightness tests (this house scored 0.43). Almost all would also meet the passive

house standard, he says, except in cases where steel is used and the client has chosen not to use specialist thermal break products at an additional cost to eliminate thermal bridging through the steel. Timber frame is certainly gaining a stronger foothold against other construction methods thanks to skills and labour shortages. “I think with the building regulations, timber frame ticks an awful lot of boxes for BCAR [the Building Control Amendment Regulations in Ireland, which require an assigned certifier on construction projects] and all sorts of paperwork and everything, especially for


CASE STUDY

WEST IRELAND

It is always a comfortable and consistent ambient temperature.

architects and engineers,” Nee says. Following a minor hiatus between final planning permission and building the foundations, construction finally got underway in late 2018 and was completed in May 2019. “I think the level of commitment from the builders is visible; it looks like a well-constructed house,” Mark Stephens says. The finished and fairly large dwelling (276 m2) is heated by an EcoForest geothermal heat pump, and also features two Vent-Axia mechanical ventilation with heat recovery (MVHR) units. The house also qualifies as a nearly zero energy building (NZEB) by virtue of the fact that its energy performance co-efficient (EPC) and carbon-performance co-efficient (EPC) beat the newly required standards of 0.3 and 0.35 under Irish building regulations respectively. Duffy and Monaghan moved in towards the end of Sept 2019. “Our immediate impression was the sense of spaciousness from the open plan living area in comparison to our previous rented accommodation,” says Duffy. “It took a while to get used to not having an open fire or stove as it’s nearly an Irish tradition to have one, but having lived here for a couple of months now we realise that it is absolutely not necessary to have one at all based on the overall spec of the house.” Their electricity bills are averaging €200 per two-month billing period based on three bills to date over the autumn/winter period “which we were very pleased about”. What do they like the most about it? “The framed views are top of our list. Also, the fact that it is always a comfortable and consistent ambient temperature, no draughts or cold spots.”

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WEST IRELAND

CASE STUDY

The timber frame makes a big difference in performance.

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WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings.

The digital magazine is available to subscribers on www.passivehouseplus.co.uk

SELECTED PROJECT DETAILS

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1 - 4 Sequence showing the build-up of the timber frame structure internally, with an Intello vapour control membrane and a service cavity insulated with Thermafleece sheep wool insulation; 5 & 6 airtightness sealing with pro clima Solitex Plus with continuous membrane running behind internal walls to minimise leakage.

56 | passivehouseplus.co.uk | issue 33

Clients: Michelle Duffy & David Monaghan Architect & passive house consultancy: Mark Stephens Architect Structural engineer: Tanner Structural Designs BER / DEAP: MCM Energy Consultants Timber frame: Long Life Structures Electrical contractor: Keith Devaney Electrical Contractors Airtightness tester: Hession Energy Cellulose insulation: Clioma House Sheep wool insulation: Thermafleece Airtightness products: Ecological Building Systems Windows & doors: Munster Joinery Ground works: Brian Callaghan Plant Hire & Ground Works Roof finish: GG Roofing Geothermal heat pump: DM Heat Pump Services MVHR: Vent-Axia

Read more about this project in detail


CASE STUDY

WEST IRELAND

IN DETAIL BER: A2 (47.94 kWh/m2/yr)

Building type: Detached 276 m2 timber frame house

Airtightness (at 50 Pascals): 0.43 ACH or 0.489 m3/m2/hr

Location: Castlebar, Co. Mayo Completion date: October 2019 Budget: Undisclosed Passive house certification: Not certified Space heating demand (PHPP): 15 kWh/m2/yr

Thermal bridging: DEAP calculations used timber frame ACDs for thermal bridging factor with specific thermal bridges also calculated. Thermal bridges also accounted for in PHPP. Y-value (based on ACDs and numerical simulations): 0.08 W/mK

Heat load (PHPP): 9W/m2

Energy bills (measured or estimated): Averaging â&#x201A;Ź100 per month to date for electricity (which includes space heating & hot water) during autumn/winter of 2019/20.

Primary energy demand (PHPP): 39 kWh/m2/yr

Ground floor: Insulated raft foundation with 200 mm EPS insulation. U-value: 0.100 W/m2K

Heat loss form factor (PHPP): 3.586

Walls: Factory-built timber frame with 100 mm rendered concrete blockwork externally, followed inside by pro clima Fronta WA membrane, 50 mm unventilated cavity, 9 mm plywood sheathing, 220 mm cellulose-filled timber stud, Intello airtightness membrane, 50 mm service cavity insulated with sheep wool insulation, and 15 mm Gyproc Soundbloc/Fireline/Moisture Resistance. U-value: 0.164 W/m2K (accounts for studs & battens)

Overheating (PHPP): 0% of year above 25C Number of occupants: 3 Energy performance coefficient (EPC): 0.287 (NZEB compliant <0.3) Carbon performance coefficient (CPC): 0.268 (NZEB compliant <0.35)

Roof: Alkor fully bonded PVC with seams, with

Novaplex coated steel soffit and fascia, followed beneath by 18 mm plywood sheathing, 38 mm ventilated cavity, pro clima Solitex Plus membrane, 300 mm timber I-joists fully filled with cellulose insulation, Intello airtightness membrane, 50 mm uninsulated service cavity, 15 mm Gyproc Soundbloc/Fireline/Moisture Resistance. U-value: 0.136 W/m2K Windows: Munster Joinery triple glazed uPVC windows, with argon filling and an overall U-value of 0.7 W/m2K Heating system: EcoForest ecoGEO 3-12 kW HTR-EH geothermal ground source heat pump with COP of 4.6, supplying underfloor heating and 300 litre hot water cylinder plus 300 litre buffer tank. Ventilation: Two Vent-Axia Lo-Carbon Sentinel Kinetic FH (K+1 & K+4) heat recovery ventilation systems, SAP Q rated, SEC Class: A+, thermal efficiency: K+1=90%, K+4=87%. Use of non-passive house certified units accounted for in PHPP. Green materials: Wood for timber frame is FSC and PEFC certified, sourced from environmentally responsible forests; cellulose insulation; sheeps wool insulation.

Kitchen Tanked

W.C

wetroom

Utility Heat Pump

Sitting Dining

Den HWC

Office

W.C

Storage

Sitting

Hall

Void

Bedroom 03

Bedroom 01

Bathroom Bedroom 02 Pop up

Wardrobe

Ensuite

Master Bedroom

Ground Floor Plan Scale 1:100

First Floor Plan Scale 1:100

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COOKING

INSIGHT

HELLâ&#x20AC;&#x2122;S KITCHEN W H Y C O O K I N G CA N D E ST R OY INDOOR AIR QUALITY

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INSIGHT

COOKING

When it comes to air pollution, we tend to worry most about things like traffic fumes and solid fuel burning — or when it comes to indoor air, condensation, damp and mould. But one of the biggest threats in the air we breathe comes from something we are exposed to almost every day, but rarely think about: cooking. John Hearne reports on the evidence for how cooking affects indoor air quality, and what we can do about it.

I

n 2015, the National Cancer Centre in Singapore carried out a study that didn’t receive much attention on this side of the world. Each year between 2010 and 2014, an average of 1,370 people in the city state were diagnosed with lung cancer. The curious finding was that three in ten of these had never smoked a cigarette in their lives. They weren’t just non-smokers; they had never smoked at all. Of these never smokers, 70% were women. The thing that tied them all together? They all spent a lot of time cooking – predominantly on woks. Research into the impact of wok cooking found that it leads to significantly increased levels of the toxicants acrolein and crotonaldehyde, substances which can attack a person’s DNA. The complicating issue for many of these women was that because they were not thought to be in a risk group for lung cancer, the diagnosis came late. It’s a shocking discovery, one of several that have brought an increasing focus on the quality of the air we breathe inside our homes. The reality is that indoor air quality, or IAQ in shorthand, has long been overlooked among the metrics we use to measure and improve human welfare. Concerns about the air we breathe have been with us since the industrial revolution, but the regulatory environment that evolved to regulate it has focused almost exclusively on the outdoors. Outdoor air, or ambient air, as it’s become known, is monitored constantly and is the subject of detailed international directives and agreements. But the reality is however that for good or ill, we’re not outside as much as we used to be. A long-term UK study on children’s lives monitored trends in the use of time from 1975 to 2015. It found that these days, the average person spends two hours a day outside. That’s 22 hours breathing in the great indoors. And what we’re learning is that it’s not actually that great at all.

Cooking & indoor air quality Max Sherman is a retired senior scientist at the Lawrence Berkeley National Laboratory and honorary professor at the University of Nottingham with over 30 years of experience in building physics, and a particular expertise in indoor air quality. He’s been at the forefront of the drive to make people more aware of adverse side effects of cooking. The first thing he’s keen to point out is that ventilation has been an issue for humans for quite some time. “Cooking is one of the things that set humans apart from their ape cousins and has been around about two million years. When humans expanded out of Africa and started to live in caves, ventilating became important. Cooking has always represented the biggest IAQ hazard humans face and we have forever been coming up with mitigation strategies. Caves had carved vents in them. The first houses didn’t have doors, but they had chimneys.” What’s emerged is that these mitigation strategies haven’t kept pace with modern life. In the aftermath of the oil crises of the 70s, homeowners – particularly in the US and across Europe – began to seal up and insulate leaky houses in an attempt to improve energy efficiency. But without well-designed ventilation, airtight homes can trap a variety of background pollutants from interior sources such as furniture, carpets, paint, etc. and intermittent sources such as from heating, bathing and washing (moisture), and cooking. The smaller and more airtight the home, the greater the potential risk. It’s important to say here that notwithstanding the impact of wok cooking as demonstrated by the Singapore study, and indeed other research, we’re not just talking about stir-fries. Sherman says that in the US, the Environmental Protection Agency now ranks indoor air quality as one of the top five health conc-

erns in the population. “If you smoke indoors that’s worse than cooking, but only a fraction of people smoke. If you have radon problems in your home, and some do depending on where they live, that can be worse, but from a population point of view, everybody cooks, so population-wide, cooking is the most significant indoor contaminate activity.” So, let’s take a closer look at what happens to the air we breathe when we engage in this most basic of human activities. Much depends on the type of cooking you’re talking about. Electric coil burners on hobs, in ovens and toasters can release fine and ultrafine particles – of which more in a minute. Gas burners can generate nitrogen dioxide, carbon monoxide, formaldehyde and particulate matter. Burning organic matter during cooking, especially high-temperature cooking like frying, broiling, and sautéing produces more particulate matter, as well as acrolein (a toxic irritant) and polycyclic aromatic hydrocarbons. The latter, abbreviated to PAHs, have been linked to skin, lung, bladder, liver and stomach cancers. Boiling, by contrast, is relatively benign, but still releases moisture into the air, which, if left unchecked, can lead to damp and mould growth. The resultant health issues have been well documented before in this magazine. Research from the University of Colorado published last year found that cooking a

Cooking has always represented the biggest indoor air quality hazard.

ph+ | cooking insight | 59


COOKING

INSIGHT

Sunday roast can drive indoor pollution levels above those found in the most polluted cities on earth. The researchers found that something as seemingly inoffensive as making toast drove particle levels way higher than expected. As English ventilation expert Ian Mawditt explains, particulate matter is important as it enters the airways and, subject to size, the lungs. “Thus, irrespective of source, this pollutant is a concern,” he says. This may seem counterintuitive given the need for food for nutrition. “Food is good for you, life-giving, etc. yes, but only when it enters the digestive system and not the respiratory system” says Mawditt. Particulate matter It’s an issue of which Ben Jones in the Department of Architecture and Built Environment in the University of Nottingham is well aware. Much of his research focuses on what are known as PM2.5, which are particles that are smaller than 2.5 micrometres across. Small enough that they can be inhaled deep into the lungs, pass into the bloodstream and build up in internal organs. Research on the impact of these particles has found causal links to respiratory disorders, skin conditions and even depression. This may actually only be the tip of the iceberg, however. Jones points out that while we have ample research on the impact of PM2.5 outdoors, there is in fact very little on the health impacts of these particles when they are generated inside the house. “The PMs we get inside are not like the PMs we get outside. They come from different

60 | passivehouseplus.co.uk | issue 33

sources. The only physical property they share is their diameter. From outside, they will come from the combustion engine, petroleum products or oil-based products. Inside they’ll come from the heating up of fat and the burning of food. What we do know is that the PMs are coated in polycyclic aromatic hydrocarbons which are carcinogenic.” He adds that while we don’t have empirical evidence to confirm this due to the relatively recent introduction of this cooking technology into the domestic kitchen, modern induction hobs are probably the safest way to cook. Max Sherman zeros in on baking and frying. “So, you’re frying something in a pan and you’ve got hot oil bubbling away. It’s making all sorts of particles that are chemically reactive. These are called reactive organic compounds and are even more dangerous than the particles that are floating around on the outdoor air, because the latter have been there for a long time and so their reactive components have all gone away. Particles that are freshly produced by combustion or cooking activities are probably worse for you than the ones that are out there.” We won’t know definitively without further research, but it’s likely that the health impacts of ingesting PM2.5 inside the house are significantly more serious than ingesting them outside. “Not all 2.5PM are created equal,” says Catherine O’Leary, a post-doctoral research student who has worked with Ben Jones on these issues. “We use the same assessment of risk for both indoor and outdoor PMs and that’s a problem. That’s a major flaw in our analysis.”

Cooking a Sunday roast can drive indoor pollution levels above those in the most polluted cities.

Emission rates of PM2.5 vary significantly depending on what’s in the pan and how it’s being cooked. To try and get more reliable data on the issue, Jones and O’Leary carried out a study with The National Scientific Authority of the Netherlands in which the team cooked four standard meals, each of which was reasonably typical of Northern European cuisine. “We were able to quantify the rate at which particles are emitted,” says Jones, “and we were able to show that if you cooked the same meal again and again, the profile of the emission has a certain pattern to it.” For example, Maillard browning, which is the scientific name for the process of browning and searing meat, generates high levels of emissions, but add water or tomatoes and the emission rate decreases rapidly. The solution? Which brings us back again to mitigation strategies. The bad news is that existing ventilation systems in most UK and Irish


COOKING

University of Nottingham

INSIGHT

homes are not sufficient to exhaust PM2.5 emissions effectively. Research by Ben Jones’ team in the University of Nottingham found that 98% of English houses are too airtight to dilute PM2.5 emissions solely by infiltration. This method alone will not bring daily mean concentrations in kitchens below the WHO guideline 24 hour average of 25 μg/m3, that is 25 micrograms per cubic metre. Controlled ventilation is therefore a vital component of any mitigation strategy. The statistical model used by the research team predicts that when applied during cooking, ventilation strategies prescribed by English building regs are adequate for less than 12% of English housing. Then there’s ASHRAE 62.2, which sets out internationally recognised standards for ventilation system design and acceptable indoor air quality. The model predicts that if this standard is deployed, it will be adequate for 75% of housing. The solution? A range hood – and building regulations across Ireland and the UK regions have all been recently updated to reflect this fact implicitly or explicitly, with extract ventilation requirements doubling if the extraction is not above the hob. There is now ample research evidence that identifies the cooker hood as the most effective way to exhaust PM2.5 – and indeed all other cooking emissions – from the kitchen. Jones and his team of researchers in Nottingham have concentrated their efforts on PM2.5 because, as he points out, ‘if you capture the PMs, you’ll also get all the volatile organic compounds from the cooking as well.’ But as with PM2.5, not all hoods are created equal. Jones describes hoods which merely recirculate filtered air as ‘probably a waste of time’. And of those that do exhaust to the outside air, the capacity of these systems varies considerably from hood to hood.

In the UK and Ireland, building regulations prescribe intermittent kitchen ventilation rates of 30 l/s adjacent to a hob – where there’s a canopy covering the hob – or 60 l/s elsewhere. In new dwellings these are obligatory, while in refurbs, it’s only necessary to maintain existing ventilation systems. The other point to make here is that these rates were chosen to remove nitrogen dioxide and moisture only. Ben Jones asserts that while a flow rate of 60 l/s trumps 30 l/s, “in reality, both are inadequate.” ASHRAE 62.2 meanwhile recommends minimum range hood extract airflow rates of 50 l/s – or as high as 150 l/s for other kitchen exhaust ventilation, including downdraft units (an extractor which rises out of the worktop when needed). “The problem now,” says Max Sherman. “is the various rating systems that are out there will tell you what the power is or what the flow rate is but not how good it is at capturing the particulates, which is what you really care about. In the last couple of years several groups have been working on standards to measure the capture efficiency of these devices so you can figure out the best way to capture the most particles.” A dialogue has begun between the largest manufacturer of range hoods and Sherman’s Lawrence Berkeley National Laboratory. He’s optimistic that the next iteration of ASHRAE 62.2 will include a capture efficiency requirement. Things are moving more slowly on this side of the Atlantic. Initial attempts by the University of Nottingham to engage cooker hood manufacturers haven’t come to anything. Passive House Plus understands the research has been submitted both to Public Health England and to the UK Ministry of Housing, Communities and Local Government, and we hope dialogue between these bodies will lead to changes in the regulatory guidance in

this area. In particular, safe exposure limits associated with indoor generated particulates should be included in the list of pollutants used to set the ventilation performance standards. The other point to make here is that you might have the best cooker hood in the world, but it won’t make any difference to the air quality in the home if it’s not switched on – let alone being left on for ten minutes after cooking, as per the guidance. Surveys have found that people frequently don’t turn on the hood because it’s noisy – a risk which increases if the regs require higher extract rates – or simply because they forget to. People sometimes only turn them on to remove smoke and odours. Many of the worst pollutants cannot be sensed, which implies that we may not be using the cooker hood when we need it most. “Whenever we give a talk,” says Ben Jones, “we ask who’s got one and who uses it. You’ll notice a drop off. And I’m as guilty as anybody. I listen to the football phone-in on a Saturday night when I’m cooking. If I’ve got a fan on that sounds like a jet plane taking off, I can’t hear the radio.” This is an area that we’re going to hear a lot more about in the coming weeks. As I write this, the Royal College of Paediatrics and Child Health, in association with the Royal College of Physicians, has just released a major report on the health effects of indoor air quality on children and young people. It’s a multi-disciplinary report that has drawn on research by Ben Jones and his team in Nottingham – and indeed on Max Sherman’s earlier work – to draw attention to an issue that has been overlooked for long enough. For more information including research papers and webinars on this topic visit the website of the Air Infiltration and Ventilation Centre, www.aivc.org.

ph+ | cooking insight | 61


GREENER CONCRETE

GUIDE TO

The PH+ guide to

GREENER CONCRETE REDUCING THE CLIMATE IMPACT OF CEMENT & CONCRETE IN BUILDINGS

Cement is responsible for up to 8% of global carbon emissions, and in this guide, sustainable design expert Jay Stuart looks at ways to minimise its environmental impact through good design, and at some of the alternative, lower carbon cement and concrete products on the market.

T

he operational energy use of new buildings has now been significantly reduced with nearly zero energy building (NZEB) standards, at least in EU countries, and the increasing use of renewable energy. Together these two strategies have reduced the carbon emissions generated in the operation of new buildings. Building regulations are also likely to require zero energy buildings (ZEB) in the near future, which should reduce the carbon emissions from operational energy use to zero in new buildings. For several years attention has been shifting to the embodied carbon of the materials, components and systems used in the construction of buildings. Research shows that the embodied carbon of the construction stage is between 30% to 70% of total carbon emissions during the life of a building. Embodied carbon is therefore the next logical focus for the building regulations. Some planning authorities in the UK and

62 | passivehouseplus.co.uk | issue 33

Europe are already requesting calculations of embodied carbon at planning stage. Embodied carbon evaluation may become a differentiator in the planning process before it is written into building regulations. Most building rating systems such as BREEAM, LEED, Green Star, and the Irish Green Building Council’s Home Performance Index recognise embodied carbon measurement and mitigation as part of minimising a building’s life cycle impacts. As we build increasingly energy efficient buildings that use less operating energy and more renewable energy, the embodied carbon of the construction stage becomes a higher proportion of the building’s total life cycle carbon emissions. If the materials used actively sequester carbon dioxide, then we can also use buildings to remove CO2 from the atmosphere. Lower carbon cement & concrete To achieve climate change targets, it is

imperative that we address embodied carbon. The use of life cycle analysis (LCA) tools to assess the carbon emissions of the whole life of a building is a necessary first step to identify where reductions can be achieved. The detailed information for LCAs will come from research databases such as Ecoinvent (www. ecoinvent.org), which describes itself as “the world’s most consistent and transparent life cycle inventory database”, and from manufacturers’ Environmental Performance Declarations (EPD), which are available for an increasing number of construction products. Concrete is one the most carbon intensive materials used in construction. This is because large amounts of CO2 are emitted when cement, one of the main ingredients in concrete (along with aggregate and water), is produced by heating limestone (calcium carbonate) to a very high temperature. Cement accounts for about 8% of global carbon emissions, which is about three to four times more than the carbon emissions


GUIDE TO

of global air travel. The embodied carbon of new construction can be reduced with low carbon design mixes for concrete, more efficient designs which use less concrete and the use of other materials and technologies in place of concrete. The cement and concrete industry has been developing lower carbon cement and concrete for a long time. By using recycled materials, developing design mixes for specific uses, and burning alternative fuels instead of fossil fuels in some cement plants, the industry has reduced the embodied carbon of concrete. Concrete mixes can now be specified which range from about 105 kg to 435 kg of CO2 per cubic metre, depending on the source of the raw materials, cement manufacturing methods and the design mix. The concrete in the substructure, foundations and superstructure account for about 55% of the embodied carbon in a typical building. The 2012 London Olympics Delivery Authority and contractors worked together to reduce the embodied carbon in all the concrete they used by 24% through careful specification of the design mixes and a further 16% re duction through rationalised design efficiencies of the structures and buildings. The use of by-products from other industrial processes as substitutes for cement and aggregates is well established, but they are not necessarily what your local

Readymix supplier will deliver unless clients, professionals and contractors specify low carbon concrete. GGBS (ground granulated blast-furnace slag, a byproduct of iron and steel manufacturing) and PFA (pulverised fuel ash, a byproduct of coal power plants) have been used as partial substitutes for ordinary Portland cement (OPC) for decades now, as has construction and demolition waste as a substitute for stone aggregates. These are often specified because they cost less than OPC or newly quarried rock. They also happen to have lower embodied carbon than OPC or newly quarried rock. In any project early discussions on this issue with structural engineers, contractors and concrete suppliers will enable the use of appropriate local design mix solutions with much less embodied carbon. Passive House Plus has previously reported about concrete block manufacturers switching all of their production to 50% GGBS without increasing costs, adversely affecting quality or slowing down production time, thanks to an accelerant developed by GGBS manufacturer Ecocem. A number of insulating concrete formwork suppliers are also offering 50+% GGBS in their formwork, while some precast concrete manufacturers are using up to 70% GGBS with 30% OPC in their products, citing increased resistance to chemical and chloride attack, improved long term strength gain and

GREENER CONCRETE

lower heat of hydration enabling large volume pours due to reduced risk of cracking. Other than embodied CO2 savings, GGBS has often been used in concrete because of the lower cost, increased strength, longer life, smoother finish and white colour it gives to concrete. Aided by the development of new accelerants, the controlled conditions of precasting and blockmaking allow a higher proportion of GGBS, but the designer/specifier must know what is possible and specify it correctly. Technically, it is possible to substitute 100% of OPC with GGBS, though in the past this has been impractical due to drying times which exponentially increase once the share rises above 30 to 50%, depending on the application. However, the development of new accelerant additives is causing this to rapidly change, and products which entirely substitute OPC with 95% GGBS and a 5% alkali reactor, such as Cemfree from DB Group (Holdings) Ltd, are now commercially available in the UK. Research and development continues and there are new processes and products which can further reduce the impact of concrete. O.C.O Technology Ltd in the UK have recently perfected a process which produces M-LS (manufactured limestone), a â&#x20AC;&#x153;carbon negativeâ&#x20AC;? aggregate that can be used in concrete to replace stone aggregates. It uses CO2 gas to treat thermal wastes (pollution control wastes from industrial smokestacks)

above Cemfree low carbon concrete was used by the Environment Agency to achieve an 88% embodied carbon reduction in sea defences at Foulton Hall, Essex.

ph+ | greener concrete guide to | 63


GREENER CONCRETE

GUIDE TO

above Concrete blocks manufactured using ‘carbon negative’ aggregate from O.C.O Technology Ltd.

and convert them into stable calcium carbonates which are blended with binders and fillers to form M-LS. This product can significantly reduce the impact of concrete when it is specified and used in place of stone aggregates. The process permanently captures and sequesters significant amounts of CO2 and, if combined with a high GGBS cement mix, a much lower carbon concrete can be produced. O.C.O have three plants in the UK and three active development projects in other countries. But like everything in the cement and concrete industry, if it’s not made locally the carbon emissions of transporting anything this heavy any distance by road may outweigh the lower embodied carbon of the materials. You may have seen various articles and news items stating that a ‘bio-concrete’ or ‘bio-masonry’ has been developed which uses bacteria to make a new type of low carbon concrete. This could be a wonderful solution, but the research is at an early stage and the best results are difficult to replicate. To the best of my knowledge it is not commercially available as a product or process. It may yet prove to be useful but at the moment it is in the R&D phase. It may be ‘bio’, but we don’t yet have evidence to indicate it is an ecologically better product. I was a partner in an EU funded research project called ‘Eco-Cement’ (2012-2015), and the soil bacteria that was the focus of this research used urea to produce enzymes which form carbonate crystals which bind particles to form something akin to concrete. In our trials we made a mortar, a plaster and a tile, but they were not very strong. Our role in the project was to do the LCA assessment of our process to assess its embodied carbon and how successful our process was in producing an ‘eco-cement’. We completed an early assessment and discovered that the only available source of urea was made from fossil fuel gas. This completely blew the product up into a high embodied carbon material, worse than ordinary Portland cement.

64 | passivehouseplus.co.uk | issue 33

We did solve this urea problem by creating our own ‘bio-urea’ in a complex integrated industrial process to make an ‘eco-cement’, but this was a completely theoretical exercise and no such plant exists. Much work remains to be done to increase its strength and durability as well as lower its embodied carbon. Since this ‘eco-cement’ is not available, and if a project is not near a source of GGBS, M-LS or recycled construction and demolition waste, then the designer can also consider minimising or avoiding the use of concrete. Design efficiencies Thornton Tomasetti, a global engineering consultancy, have recently launched a Revit BIM plug-in for building structures called Beacon which calculates the embodied carbon of concrete in a building’s structural design to inform the design process. If reducing embodied carbon in a building is a design objective, then it is possible to develop more efficient designs which use less concrete and assess their relative

embodied carbon. Accompanying such tools are integrated software systems for the design optimization and dematerialisation of structures, which can lead to more efficient and lower carbon structural design solutions. Building methods There are many building methods, technologies and systems which can contribute to the reduction of embodied carbon and they deserve separate articles. I list some of them here and it would be interesting if readers were to send PH+ magazine (info@passivehouseplus.ie) technologies or products they know about which could be added to this list for a future PH+ guide or article. I will start this list with a few that I know about: vibro-compacted stone foundation systems; floating/raft foundation slabs; metal helical screw or auger piles; CLT timber structures; hempcrete blocks; to name a few. Foundations I have included one build method though, as

below Galway-based concrete product supplier Coshla Quarries manufacture blockwork as standard featuring 50% GGBS from Ecocem.


GUIDE TO

it does represent a greener use of concrete, rather than an alternative to concrete: an insulated slab on vibro-compacted stone. Vibro-compacted stone foundation technology is well developed and has many advantages. There are different techniques but in essence a specialised machine vibrates a pile of stones into the soil until the compacted stones achieve the required bearing capacity. Low rise buildings can spread the foundation load with a reinforced ‘floating slab’ on a 200 mm layer of compacted stones as was done at the Silken Park housing scheme in west Dublin. Here a thin 100 mm reinforced concrete slab was poured into a ‘passive insulated formwork’ of prefabricated EPS insulation to help achieve the passive house certification. By avoiding conventional trench strip foundations there were cost savings in excavation, carting away subsoil and pouring concrete to fill up the trenches. If the concrete slab also had a high GGBS mix with recycled aggregate or M-LS it would be an extremely low embodied carbon solution. One alternative to mention in this article, which, in uncrushed form, is a constituent ingredient in concrete: stone. Stone was used structurally in buildings for centuries but it is now mostly used as a thin cladding material. Amir Taha, a UK architect, has recently completed a 6 storey structural stone building in Clerkenwell, London which uses limestone cut at the quarry by stone masons to create columns and beams and other elements of the building. It is estimated that the embodied carbon of this quarried stone is only 15% of the equivalent structure in reinforced concrete. Stone can last for centuries but reinforced concrete is variously estimated to last 75 to 120 years depending on the design mix. Conclusion It is clear that the need to reduce the environmental impact of embodied carbon in

EMBODIED CARBON is defined as the CO2 emissions caused by the extraction, manufacture, transportation, assembly, maintenance, replacement, deconstruction, disposal and end of life aspects of the materials and systems that make up a building.

construction is becoming an increasingly significant issue for the industry. To achieve lower embodied carbon construction the industry needs to adopt the specification of low carbon construction methods, materials and processes as an integral part of the briefing, design, specification and procurement stages of a project. There are many alternatives to concrete which, along with modern methods of concrete production, means there is lots of potential to reduce embodied carbon. But concrete is manufactured locally so the embodied carbon of concrete varies considerably by location, and it needs to be carefully specified to achieve its potential. The business case for lower embodied carbon buildings is being driven first by environmental assessment and endorsement systems like BREEAM and LEED, followed by the corporate social responsibility and environmental policies of some client organisations which are now increasingly being required by financial institutions. Some planning authorities are asking for embodied carbon information and estimates, and there have been discussions at industry conferences about regulating embodied carbon using the building regulations. The London Olympics Delivery Authority achieved significant reductions in embodied carbon in its concrete and saved money in the process. Anglian Water has demonstrated capital cost savings of between 30-50% by tracking embodied carbon in their infrastructure projects, which are predominantly constructed in concrete. It is my opinion and experience that there are more sustainable solutions for every process and product in the building industry, and if used in an integrated design, there can also be significant cost savings. I suggest that reducing the embodied carbon of buildings will result in reduced capital costs of construction when the industry scales up to meet this challenge.

CARBON SEQUESTRATION is the long-term removal and sequestration (separation and storage) of carbon dioxide from the atmosphere to reduce atmospheric carbon dioxide pollution to mitigate global warming.

GREENER CONCRETE

EMBODIED CARBON FOUNDATION COMPARISON Michael McCarthy of leading cost consultants MMC Quantity Surveyors conducted a comparative analysis of embodied carbon emissions of two common foundation systems in low energy buildings: a passive slab foundation system, and a traditional strip foundation, in both cases for a 100 m2 typical semi-detached house. The passive slab system in this case consisted of the KORE passive slab of EPS 300 with a ring beam, with 50% GGBS concrete assumed, compared to an insulated strip foundation system made with OPC. With 50% of cement in the concrete substituted for GGBS, the slab’s total concrete mix achieves a 27% reduction in carbon dioxide equivalent (CO2e) over standard concrete (28N). Due largely to this fact, a reduction in excavated material, and the substantial reduction in the quantity of concrete required, the system achieves a 51% reduction in embodied CO2e emissions – a reduction from over 17 tonnes to 8.3 tonnes. In addition, according to MMC the passive slab costs about €2,000 less to construct than the standard strip foundation. If a higher percentage of GGBS is used, along with the likes of OCO’s M-LS aggregate, a substantially higher reduction could be achieved. That said, it is also possible to achieve significant reductions with strip foundations too, by changing the concrete recipe as per above – albeit without reducing the quantity of concrete, and the additional scope for emissions reductions this offers.

A fully referenced version of this article is online at www.passivehouseplus.co.uk

above, left to right The foundation system used at Silken Park consisted of vibro compacted stone; a KORE passive slab system; and consequently a significantly reduced concrete slab pour.

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MARKETPLACE

PA S S I V E H O U S E +

Marketplace News Don’t see MVHR as a heating or cooling system — CVC Direct

Partel launches recycled PET structural thermal break

(above) Schematic image of a Brink Flair MVHR system in a typical house.

T

he idea that mechanical ventilation with heat recovery (MVHR) systems are designed to provide heating or cooling remains a common misconception about the technology, according to leading supplier CVC Direct. “A common call to the office every winter, is that the MVHR system is not providing enough heating. Another is in the summer stating that the MVHR system is not providing enough cooling. These are common misconceptions of an MVHR system,” CVC Direct’s Nicholas Vaisey told Passive House Plus. “MVHR works by extracting warm moist air from ‘wet’ rooms and supplying filtered, warmed air to the bedrooms, living rooms etc. The extracted warm air is drawn through a ducting system, back to a main unit which contains a heat exchanger. At the same time fresh air is bought in from the atmosphere. The extracted air is used to warm the incoming fresh, filtered air. This fresh, filtered, warm air is then reintroduced back into the property via a ducting system. “Our Brink MVHR units provide a heat recovery efficiency of up to 91%, and while this is highly efficient, there

is still a minimal amount of heat loss — although considerably less than if using extract only ventilation and trickle vents in windows. Typically, when the extracted air is 21C and the outside temperature is 0C, the air that is supplied back into the building will be 19C. The MVHR unit itself does not provide any heating, it just recovers what is already there.” Vaisey continued: “Summer bypass is designed for warmer periods, where fresh air can be bought into the property, whilst bypassing the heat exchanger. Since the air avoids the heat exchanger, it is not preheated by the extracted warm air. Solar gain in the summer months has the potential to provide a lot of heat in a property, especially when there are large expanses of glass. The cooling effect of the summer bypass is limited and often not enough to counteract the heat gains. The most effective methods to deal with solar gain are through shading and effective design of the building.” “An MVHR system on its own does not provide cooling or heating, though there are elements that can be added to the system to provide these functions.” •

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L

eading sustainable building product supplier Partel has a launched a new 100% recycled thermal break product. ALMA THERM is a hi-performance panel for structural insulation, and meets the highest technical and ecological standard for reducing thermal bridges, according to the company. The product is 100% recycled and PET-based, and at the end of its life cycle it can be recycled again. It conforms to construction material class E and is noted for its high compressive strength, excellent mechanical strength, as well as efficient thermal break and lightweight composite structure. It is compatible with a large number of adhesive and sealing systems. Thanks to its very low thermal conductivity, ALMA THERM is suitable for thermal separation, for use in window or door profiles in commercial and residential projects to improve the energy efficiency of the building. Moreover, the water absorption of the material of less than 2% is extremely low. ALMA THERM can be processed in two different density classes (115 kg/m3 and 180 kg/m3) and can be supplied in two standard dimensions, 1218 x 1005 x 50 mm and 1218 x 1005 x 75 mm. Bespoke sizes upon request. For more information see www.partel.ie. • (above) ALMA THERM 100% recycled PET thermal break.


PA S S I V E H O U S E +

Passive house cert for pro clima liquid membrane

MARKETPLACE

New passive house developer breaks ground in Bradford

KORE

(above) A computer generated image of the Pure Meadows scheme.

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(above) Spray applying AEROSANA VISCONN to construction timbers.

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cological Building Systems has announced that another component from the pro clima range of intelligent airtightness products has attained passive house approval. Niall Crosson, group technical manager with Ecological, stated: “Following the successful passive house approval for the INTELLO PLUS airtightness system, which attained the best ever airtightness component results to date by the Passive House Institute of 0.0 m3/(m2h) , pro clima’s liquid applied intelligent airtightness paint, AEROSANA VISCONN, has also attained passive house approval to the highest category of phA. This confirms AEROSANA VISCONN’s ability to perform and attain the required levels of airtightness to meet passive house levels of performance.” AEROSANA VISCONN is a high-quality, water-based acrylic dispersion which can be applied as a spray or using a brush/roller. The sprayed on liquid film forms a seamless, extremely elastic, airtight and vapour-resisting protective layer once it has dried, and may be applied internally or externally. AEROSONA VISCONN is supplied in 10L buckets and can be plastered or painted over, and is suitable for use in conjunction with the pro clima range of sealing tapes and adhesives. AEROSANA VISCONN can be used to maintain airtightness behind intermediate floor timber joists when fixed directly to the face of blockwork, instead of using a strip of airtight membrane or a parge coat of plaster. It is also a suitable substrate for bonding plasterboard to. It is humidity-variable with an sd value range of between 0.13 m and 10 m. This means that it may be used in conjunction with a vapour open racking board such as ELKA Strong Board and timber joists, without the risk of trapping moisture within timber members, while at the same time attaining an airtight seal. AEROSANA VISCONN presents no health risk to homeowners or installers, Ecological stated, and has been assessed in accordance with the onerous hazardous substance test according to the AgBB evaluation scheme / ISO 16000. It is suitable for use in healthy low energy buildings such as those conforming to Sentinel Haus principles. For more information, please see www.ecologicalbuildingsystems.com. •

new UK property developer specialising in passive house projects is currently on site with its first scheme, Pure Meadows in Oakenshaw, Bradford. The development of two houses will be built to the passive house standard, with passive house design by Claire Jamieson of PHI Architecture. At the time of writing site works were being completed in preparation for the construction of the timber frame dwellings. “Pure Meadows is a gem that’s tucked away from the hustle and bustle of city life while being minutes away from major motorway links,” Pure Haus director Kevin Pratt told Passive House Plus. The scheme will feature a landscape-sensitive design, biodiversity-friendly landscaping and a high-quality palette of contextual materials including timber and stone cladding. The dwellings will also feature rainwater harvesting systems. A passive house development represents something of an unlikely destination for Kevin Pratt and his business partner David Bradley-Bowles, who have a background as landlords in the buy-to-let sector, with a history of renovating and improving old properties. Kevin says that learning about the Climate Innovation District in Leeds — a new pioneering sustainable neighbourhood in the city — convinced the pair to change tack. David then attended the International Passive House Conference in Germany after hearing about the standard. “The Passive House Institute had a huge influence on developing the company’s vision,” said Kevin. “We found that passive house principles were very consistent with the company’s own ethos of sustainability, quality, health and comfort. On return from the trip a lot of research went into establishing if it was commercially viable to build comfortable, sustainable, well-designed homes.” He said that the trip completely revolutionised how he and his partners wanted to do business. “The affect was so substantial we found ourselves promoting passive house to anyone who would listen. There was a new buzz within the company.” He said that Pure Haus has found the UK passive house community hugely supportive and helpful thus far, and welcomed the community’s openness in sharing its resources, knowledge and skills. “We are very keen to grow the company and are open to conversations with people who have land opportunities, or who are interested in investing in a sustainable company.” For more see www.purehaus.co.uk. •

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Design your MVHR for a pollution-free home — Solarcrest

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eading ventilation supplier Solarcrest has advised anyone specifying a mechanical ventilation with heat recovery (MVHR) system to ensure it is properly designed to deal with local air pollution issues. “With MVHR it’s important to consider acoustics, hygiene, longevity and functionality, but if you want pollution-free air you also need to add advanced filtration to your wish list, as well as extra fan power to compensate for the air resistance those filters create,” Eliot Warrington of Solarcrest told Passive House Plus. Growing concern about the health effects of airborne particulate matter (PM2.5) and NOx pollution from traffic fumes have increased demand for MVHR, as it’s the only ventilation system that can properly filter incoming air, Warrington said. Most MVHR units come with a basic G4 ‘debris’ filter that Warrington said should normally be vacuumed every three months and replaced annually. This collects larger

airborne particles like leaves, insects, dust and muck. “Unfortunately, a G4 filter doesn’t stop the micro particles that do the most damage when inhaled. It certainly won’t stop NOx gasses,” Warrington said. “To stop most PM2.5 micro particles you need an F7 filter. It won’t stop them all but it’ll reduce them to a safe level. To stop NOx gasses from vehicle emissions you also need an activated carbon filter.” “Most manufacturers offer a G4 to F7 upgrade, but that involves swapping the G4 for an F7, which means the F7 micro filter is stopping larger debris as well as harmful particles 36 times smaller than a grain of sand. It’s going to get clogged in no time at all and it’s difficult if not impossible to vacuum. What you need is an F7 filter for tiny stuff as well as a sacrificial G4 to protect it, and a machine designed to work with both— potentially a NOx filter too if your property is anywhere near a road.” “You’re also going to need to size the fan

unit accordingly. A G4, F7 and NOx filter adds almost as much static pressure as the rest of the ducting combined. Needless to say, there’s more to designing MVHR than simply drawing lines on your floor plan.” • (below) A side by side comparison of MVHR filters at a suburban property. Top left is a new F7, top right is the F7 after one year (with G4 installed too), bottom left is a new G4, bottom right is a G4 after three months.

Future Homes is “all talk no action” — George Clarke

(above) TV architect George Clarke condemned the lack of ambition in the government’s Future Homes Standard.

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eading TV architect George Clarke has slammed plans for the government’s Future Homes Standard as “all talk no action” and being “too little and taking too much time”. Clarke is well known as presenter of leading Channel 4 programmes such as ‘George Clarke’s Amazing Spaces’ and ‘The Restoration Man’.

Writing on the Mitsubishi Electric blog, Clarke said the standard is too slow in coming, and does not go far enough to address the climate and ecological emergency. The proposed Future Homes Standard aims to introduce a “meaningful but achievable uplift in energy performance” in 2020, and then to implement the

full Future Homes Standard in 2025. The government claims the final standard will achieve a 75% to 80% reduction in carbon emissions compared to current regulations. Public consultation on the standard closed early in February. The government “envisage research into the Future Homes Standard to commence from 2021, alongside the establishment of an industry Taskforce, with research continuing into 2023... with the intention of consulting on the implementation of the Future Homes Standard in 2024.” But Clarke railed against this timeframe, writing: “We don’t have time for five years of chit chat and consultation to do what we all know is easy and is the right thing to do! “Are we really going to spend five years talking about whether to install more insulation, install triple glazing and replace our gas boilers with low carbon air source heat pumps? It’s too little and taking too much time.” “I support the idea of the Future Homes Standard, just as I supported the zero carbon homes policy that Gordon Brown announced in 2006. “But government is far too slow and far too incompetent when it comes to doing the right thing in making the changes the home building industry and the environment desperately needs to see. We need big change and action right now.” George Clarke is a brand ambassador for Mitsubishi Electric. To read his full blog post visit tinyurl.com/georgeclarkeFH. •

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T O BY C A M B R AY

COLUMN

See how skinny these walls are! How will we look back on the houses we are building today in the next century, and beyond? Toby Cambray takes an imaginative look into the future… Good Morning, you must be our historic building adviser? Yes, that’s right, what a fascinating example you have here. I noticed there are several like this close by, this must have been one of those speculative developments.

leaves less than 100 mm for insulation. And would you believe, a third of that is fresh air?! It’s probably a plastic foam insulation, but goodness knows what state it’s in now. Now, what have you noticed about the ventilation system?

that would penalise this type. Nowadays we understand the importance of density and compact buildings; notice how little green, outdoor space there is – it’s all taken up by houses or given over to “cars”. And how about the floor?

Um…. Yes indeed. Well, come on in, let’s see if we can find anything interesting. Personally, I’m all for knocking these things down, they haven’t been fit for purpose since they were built, but they are becoming unusual now and some people are lobbying for them to be protected as important historical examples. Oh absolutely, these buildings have a great deal to tell us about the way people lived in the early 21st century, it wouldn’t do to tear them down and put up some gaudy modern box instead. Take, for example, this door; you see how it’s not timber, but a type of plastic they used to call uPVC, made to look like timber. And note this hole in the middle? People used to send messages on paper, and they were delivered through this hole. Horribly leaky of course. The windows are the same. This is remark-

Well, it’s arguably the elephant in the room. That’s right! There isn’t one! Well, there are these rather charming fans in the bathrooms, but they probably never did very much. And this white box is how they used to heat such buildings. This might sound far-fetched, but our ancestors used to burn a flammable gas inside these boxes to keep warm. Very quaint, wouldn’t you say? The extension seems to be mid-century, very much after the fashion of that period, and you can see the insulation is very slightly thicker, it does detract from the original but it’s all part of the rich tapestry of the building. This house must have been built shortly before the major reforms to the energy regulations. The first few decades of the 21st century were quite interesting in that regard, in a morbid sort of way. At that time, the climate catastrophe was understood in

Yes, you could say it’s the elephant in the whole house, or at least the ground floor. Indeed, it appears to be creating some issues throughout the building. Presumably this is a result of the proximity to the river, and the low-lying nature of the plot. One can only assume that the river level was lower back then. It seems unlikely it was built with the intention of maintaining a hundred millimetres of water over the floor. Well I think I’ve seen enough. Thank you for inviting me to work with you on this, it’s a rare example that really brings the folly of this type of building to life. I suppose we’re fortunate as a society they are mostly gone now, but it’s important to preserve some examples so we can learn from the mistakes of the past. n

Our ancestors used to burn gas to keep warm. Very quaint, wouldn’t you say? able, these are probably original. Look, double glazing, and you can still see through some of the units. We must preserve these. You might be able to find someone to rebuild the glass units with new argon, although taking these out without damaging the frame is a specialist job now, that plastic will be very brittle. Still, the modern imitations are quite convincing unless you look very closely. While we’re here, look at these reveals, see how skinny these walls are? Knock on the wall, go on? You’d be forgiven for thinking this is a lightweight building, but this is actually an artisan wall lining method called ‘dot and dab’. There are a few specialists still able to do it like this, but they are a dying breed. The plasterboard is stuck to a cavity wall, but of course that

70 | passivehouseplus.co.uk | issue 33

great detail by climate scientists, but for a remarkably long time, very little meaningful change was made. There were incremental improvements, which were chasing quick, cheap and easy fixes; in retrospect we know they were neither cheap, or easy, or even fixes, long-term. There was an obsession with trying to add technological fixes, rather than re-think how buildings were made. During this period building separate houses like this was unbelievably lucrative, and a small number of developers had a disproportionate influence over policymakers. Some speculate that the house barons worked hard to maintain a mechanism in the regulations that failed to reflect the poor performance of detached houses. At that time, they fetched the best prices, so the builders resisted anything

Toby Cambray is a founding

i w  ww.archdaily.com/450212/why-japan-isdirector at Greengauge and crazy-about-housing leads the building physics team.

He is an engineer intrigued by how buildings work and how they fail, and uses a variety of methods to understand these processes.


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i m a g e : L A R C H C O R N E R PA S S I V H A U S , designed by Mark Siddall at LEAP Architecture and built by Andy Mackay at Mac Eye Projects, with Green B u i l d i n g S t o r e U LT R A w i n d o w s & d o o r s , MVHR and airtightness products. photo: © Mac Eye Projects, LARCH CORNER PASSIVHAUS.

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Certified CLT Passivhaus, London Tectonics Architects Airtight result: 0.29 ac/h @ 50 Pa Annual Heating Demand : 14Kwh/m²/yr

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