5
These figures show how much the average household would spend 5 7used by individual households. Th water and is not based on energy like TVs, computers and cookers, and electricity generated by micro
17 5
[%]
[%]
Energy Efficiency Rating
78
88
The gr home.
The hi be.
78
The po recom
88
The av Englan
Project Energy Balance
The EP assum may no occupa
Supplied Energy per Month
Top actions you can take to save money and ma 6522.6
Recommended measures 1 Internal or external wall insulation 2 Floor insulation (solid floor) 3 Low energy lighting for all fixed outlets
4000 2000
0 See page 3 for a full list of recommendations for this property.
Jan. Feb. Mar. Apr. May. Jun.
Jul. Aug. Sep. Oct. Nov. Dec.
[kWh]
To receive advice on what measures you can take to reduce your ene 0 you to mak call freephone 0800 444202. The Green Deal may enable
2000 4000 6000 Emitted Energy per Month
Gillard Associates Ltd Thermal Blocks
De Carbonising Pentir Hir: Heol Y Pentre, Pentyrch
Zones Outline Proposals Assigned
Thermal Block 001 Pentir hir
Total:
14
14
Operation Profile Residential
Gross
17
17
November 2020
Environmental Impact Source Type
Source Name
Primary Ener kWh/a
Outline Proposals
Contents
1 Introduction
1. Introduction
Introduction
2. Brief
This report is prepared in respect of the remodelling of Pentir Hir, Pentyrch.
3. Assessment of Building
4. Retro Fit Technologies 5. Calculations 6. Conclusions
The property was purchased a year ago by the clients. Whilst it offers good spatial accommodation, they are looking to modernise the building, to make it more energy efficient and comfortable to live in. They would like any solution to address problems of damp and moisture penetration and aspire to a sustainable lifestyle. They would like to achieve a nett zero carbon solution as long as the steps needed are · practical · affordable (specified budget £200,000) · timely (works must be completed by September 2021) This report is arranged as follows: a) the outline brief is described in more detail. b) the building is assessed in terms of its spatial characteristics, to include accessibility, aesthetic appearance and functionality as a 'forever home'. The building's fabric, its performance generally and any shortfall in delivering thermal comfort and energy efficiency is also discussed. c) there follows a discussion of the possible measures which may be taken to increase energy efficiency and improving thermal comfort. d) finally, given the constraints of the brief, a set of recommendations is provided which in the professional opinion of the author, which will optimise the dwelling and 'future proof' it. The recommendations are backed up by calculations and approximate costings so the client can way up the designa dn make informed adjustments as required.
page 2/16
Gillard Associates Ltd provide architectural services and specialise in sustainable design. The firm has a reputation for outstanding work in the following areas: - low energy housing - deep retrofits and decarbonising of older housing stock - community projects - conservation and restoration of historic buildings The company founder Alan Gillard has worked extensively with traditional and modern methods of construction. He has accumulated 25 years of hands on and practical experience by acting as architect and project manager on a wide range of building types in the private and public sectors. This is backed up by theoretical knowledge gained by post graduate study in Environmental Design.
GILLARD ASSOCIATES architecture and design
Decarbonising Pentir Hir Pentyrch
2 Brief
additional bathroom suggestion
boiler
2.1 Spatial gas combi boiler
Generally the existing house provides sufficient and attractive accommodation for the clients’ needs so the main aspect of the brief is in regard to thermal comfort, sustainability, and damp proofing: ie, the low energy retrofit.
Bathroom exposed stone and brick wall
Landing
Lobby
Landing
carpet floor
exposed floorboards
exposed floorboards
Bedroom
However, as their 'forever home', the brief also extends to exploring solutions to other spatial issues: ● lack of second bathroom upstairs ● plant room/tech room ● pottery ● orangery ● other sustainability solutions
Bedroom Bedroom
Bedroom
Bedroom
exposed floorboards
N
FIRST FLOOR
2.2 Access
rwp
Present means of access from the drive is via a small flight of external steps which gave access to a level apron around the building. Neither of the two entrances are satisfactory as visitors enter directly to the kitchen or have to traverse the elevation which somewhat compromises privacy.
Utility Shower
old single glazed window
i/c
i/c
i/c
The level changes from the drive to the front door are challenging.
2.3 Heating
areas of damp noted
exposed stone and brick wall
sp
svp
approx location of electric meter
approx location of water main
exposed beams at ceiling level
non compliant balustrade
rwp
Dining
Sitting
Lounge
potential space for reception/ lobby/ orangery
Kitchen
The dwelling is currently heated by a wet system of radiators linked to a gas combi central heating boiler and controlled by room thermostats and TRVs. The clients report that the building is cool in winter and the use of the wood burning stoves and room heaters is necessary for thermal comfort.
rwp
rwp
2.4 Externally
existing kitchen door unsuitable as reception
gas meter rwp
rwp
awkward steps
rwp
doors rotted
failed glazing
doors rotted i/c
rwp
rwp
in situ concrete paving
The dwelling is ideally situated on a large south west facing and south west sloping. It is relatively sheltered by mature trees and open to sunlight virtually all year round, maximising the contribution from solar gain. There is great potential for mounting solar panels on the extensive roof. The roof is also suited to collecting rainwater. Due to the fall across the site there is scope for installing RW harvesting tanks which can store water for use on the garden and other applications.
rubble stone dwarf wall
stone paving
alternative space for orangery
GROUND FLOOR
garage under sized existing front door compromises privacy
page 3/16
Outline Proposals bathroom extension
2.5 Outline Design
OUTLINE DESIGN PROPOSALS
new entrance ramp
new family bathroom new door
Bathroom wardrobes new master bedroom suite
Whilst the original appointment concerned the EEMs, following the initial meeting the client requested an outline design.
Ensuite
This addressed: ● the need for an upstairs family bathroom which was not ensuite ● a reorganised utility room to accommodate the HP and DHW tank ● an orangery/conservatory which incorporated a new entrance sequence to tackle privacy issues and stepped access
Lobby
Dressing
Landing
Bedroom
'front door'
new door position
N
The proposal was rejected but served to refine the clients' requirements which are now much reduced in scope and limited to: ● an ensuite bathroom to the wet bedroom in a new two storey building ● a ground floor 'granny flat'
Bedroom
Bedroom
Bedroom
block up window to create tech room Heat pump and DHW tank
rwp
security gate
potential balcony
raised paving hides manhole covers
DHW
blue dotted line indicates circulation route
Shower
i/c
ramp removed level access paving
old single glazed window
i/c
i/c
new entrance ramp
gas meter rwp
rwp
However, the design of this revised scheme is outside the scope of this report which should be read as a way to address the energy efficiency measures needed to make the house as its stands into a carbon neutral dwelling.
sp
svp
approx location of electric meter
New entrance sequence provides ramped access and new arrival point at 'front door' which offers a choice of circulation routes to kitchen or living areas. The blank east facade provides privacy from visitors approaching the house. Access is now easilty controlled and provides additional security.
exposed beams at ceiling level
planting and screening 'front door' plaster exposed stone and brick wall
Dining
Sitting
Lounge
From the energy assessment a draught lobby will help reduce heat losses when doors are opened.The glazed facades will generate a reasonable amount of solar gain and remove the need for overinsulating the external wall below the new flat roof level. The flat roof offers an opportunity to provide a balcony to the upper master bedroom and in any case will offer green roof habitat for insects and butterflies.
Kitchen
draught lobby to increase energy efficiency and provide secure reception
2.6 Key Principles for Energy Efficient Refurbishments
Lobby
Aesthetically the wrap around 'orangery' ties the project with the landscape and refocuses the living spaces to the centre of the plan: and addresses the large garden in a way which justifies the status of the plot. Rev
Description
Date
By
N
separate access to living areas
rwp
Outlined here are the four key principles that are essential for successful and effective energy efficient retrofits and that need to be considered as part of a ‘whole house strategy’.
Proposed Design Relatively inexpensive lightweight glazed extension provides a new facelift whilst keeping traditional appearance, and allows inside/outside seamless living for all weather enjoyment of garden.
Utility
Scales @ A1 1:50, 1:209.78, 1:203.80, 1:295.41 Purpose of Issue
i/c
File: C246 Davidson.pln
PRELIMINARY ISSUE FOR DISCUSSION ONLY
GILLARD ASSOCIATES
Orangery
The Quaypad Cardiff Marina, Watkiss Way Cardiff CF11 0SY Tel No +44 (0)2920 229 133 contact@gillardassociates.co.uk
covered seating area
architecture and design
Client
Davidson access to pottery
Job Title
Date: 29/10/2020
Remodelling of Pentir Hir Pentyrch Cardiff
These principles are the pillars on which the 'PassivHaus' formula have been built and are considered to be the best way to achieve a low energy dwelling whilst delivering a healthy environment for the occupants. a) Insulation For walls, floors, roofs, lofts and windows, energy efficiency obviously depends on good levels of insulation. b) Airtightness Airtightness (or reduction of draughts) is an often overlooked aspect of energy efficiency which can make a huge impact on the warmth and comfort of a home.
page 4/16
Drawing Title
Plans As Proposed line of roof over
sliding louvres for shading/privacy
Drawing No
Rev
AL(0)3 This document and its design content is © Gillard Associates Ltd. It shall be read in conjunction with all other associated project information including models, specifications, schedules and related consultants documents. Do not scale from documents. All dimensions to be checked on site. Immediately report any discrepancies, errors or omissions on this document to the Originator. If in doubt ASK.
c) Continuity of insulation (or minimising ‘thermal bridging’) To work best, insulation needs to work in a continuous ‘blanket’ around the house, minimising any gaps in the insulation (known as ‘thermal bridges’). Examples of ‘thermal bridges include through stones through cavity walls or gaps in insulation where the wall meets the roof, which breaks the continuity of insulation and loses heat out of the building.
The importance of reducing ‘thermal bridges’ increases as the level of insulation increases. d) Controlled Ventilation As airtightness improves in a building, it is also vital that suitable approaches to ventilation are considered carefully, so that there is no impact on occupant health or building structure.
Decarbonising Pentir Hir Pentyrch
3 Assessment 3.1 Construction The detached single dwelling known as Pentir Hir is a row of former traditional cottages which were consolidated into one building approximately 50 years ago. The structural walls are assumed to be mainly random rubble stone rendered externally and plastered internally. The roof appears to have been extended upwards at the time of conversion. The original windows are of a mock Georgian style single glazed and were installed at the same time. There has been a programme of window replacement in the last decade or so and most of the windows are now double glazed. The external doors or generally glazed or half glazed and or a mixture of original and replacement doors. Some are in a very poor state of repair and the client is in the process of replacing them. There is a more modern single storey extension on the North side of the dwelling which contains a utility room and shower room. The walls of this addition are cavity blockwork and it is assumed that the construction generally conforms to more recent building regulations, say around 1990.
traditional chimney stack
These defects are considered to be a result of the poor thermal performance of the dwelling and will be discussed in a later section.
insulated ceiling and ventilated roof void
large south west facing roof
timber casements double glazed
500mm thk rubble stone walls with cement render and plaster
thick cement render open porch solid concrete apron
modern lean to extension
The survey report commissioned by the clients at the time of purchase provides a detailed analysis of the building elements and whilst there are some defects requiring making good work the overall condition of the building is relatively sound. There are however some areas of damp on the inner faces of external walls which are noted on the plans.
concrete tiles on rafters on purlins
woodburning stove single glazed external timber doors in poor condition
solid floors assumed to be concrete slabs
Cutaway construction page 5/16
Outline Proposals uncontrolled flue ventilation
3.2 Energy Assessment
cold roof
The EPC surveyor has identified the main elements which contribute to inefficiencies in regard to energy consumption. These are reproduced below. The report differentiates between the original construction, and the add on extension which is more modern.
Energy Performance Certificate
poor thermal insulation
thermal bridging at eaves
Pentir Hir, Heol y Pentre, Pentyrch, CARDIFF, CF15 9QE Dwelling type: Date of assessment: Date of certificate:
not airtight
Detached house 30 January 2019 31 January 2019
poor thermal Use this document to: insulation
thermal bridging at reveals
• •
Reference number: Type of assessment: Total floor area:
8151-77 RdSAP, 177 m²
Compare current ratings of properties to see which properties are more energy efficient Leanandtomoney shower Find out how you can save energy by installing improvement measures
room: sub standard Over 3 years you could save thermal insulation
Estimated energy costs of dwelling for 3 years:
Estimated energy costs of this home
Pentir Hir, Heol y Pentre, Pentyrch, CARDIFF, CF15 9QE 31 January 2019 RRN: 8151-7729-0830-0760-3976 poor insulation thermal bridging
Above: west gable wall left exposed as feature Below: cold roof construction with insulated ceiling
Current costs
Potential costs
Lighting
£ 423 over 3 years
£ 291 over 3 years
Heating
£ 4,068 over 3 years
£ 2,481 over 3 years
Hot Water
£ 318 over 3 years
£ 318 over 3 years
Totals £ 4,809
Element
Description
Walls
Sandstone or limestone, as built, no insulation (assumed)
like TVs, computers and cookers, and electricity generated by microgeneration.
Energy Efficiency Rating Energy Efficiency
The potential rating shows the e recommendations on page 3.
Pitched, 150 mm loft insulation Pitched, insulated (assumed) Solid, no insulation (assumed)
—
Solid, insulated (assumed)
—
Windows
Mostly double glazing
Main heating
Boiler and radiators, mains gas
Main heating controls
Programmer, room thermostat and TRVs
Secondary heating
Room heaters, wood logs
Hot water
From main system
Lighting
Low energy lighting in 54% of fixed outlets
Current primary energy use per square metre of floor area: 244 kWh/m² per year
page 6/16
The graph shows the current en home.
The higher the rating the lower y be.
Cavity wall, as built, insulated (assumed)
Floor
£ 3,090
These figures show how much the average household would spend in this property for heati Energy Performance Certificate water and is not based on energy used by individual households. This excludes energy use
Summary of this home's energy performance related features
Roof
Po
The average energy efficiency ra England and Wales is band D (r
The EPC rating shown here is b assumptions about occupancy a may not reflect how energy is co occupants.
Top actions you can take to save money and make your home mo Recommended measures
—
Indicative cost
1 Internal or external wall insulation
£4,000 - £14,000
2 Floor insulation (solid floor)
£4,000 - £6,000
3 Low energy lighting for all fixed outlets
£60
See page 3 for a full list of recommendations for this property.
To receive advice what measures you can take to reduce your energy bills, visit www.simple The assessment does not take into consideration the physical condition of any element. ‘Assumed' means thatonthe The Green Deal may enable you to make your home warmer and insulation could not be inspected and an assumption has been made in the methodology based call on freephone age and 0800 type444202. of construction.
See addendum on the last page relating to items in the table above.
Decarbonising Pentir Hir Pentyrch
3.3 Thermal Modelling Performance The survey data was used to build a 3D model of the dwelling. An energy schedule wasEnergy then simulated so that Evaluation: incidental asAs wellExisting C236 Remodelling Pentir Hir as primary energy consumption could be modelled and compared against real world data supplied by of the client. Energy Cost
Energy Performance Evaluation: As Existing
17
C236 Remodelling of Pentir Hir Key Values
Building Geometry Data Gross Floor Area: Treated Floor Area: External Envelope Area: Ventilated Volume: Glazing Ratio:
Remodelling of Pentir Hir 51° 30' 0" N 3° 12' 0" W 100.00 m Strusoft server 26/10/2020 18:50 171.88 107.53 420.56 461.66 5
m² m² m² m³ %
Building Shell Performance Data Infiltration at 50Pa: 7.29
ACH
U value 1.34 2.01 - 2.01 0.11 - 3.22 2.02 - 2.02 1.97 - 3.64
[W/m²K]
Specific Annual Values Net Heating Energy: Net Cooling Energy: Total Net Energy: Energy Consumption: Fuel Consumption: Primary Energy: Fuel Cost: CO2 Emission:
297.69 0.00 297.69 339.05 339.05 418.03 19.09 73.23
kWh/m²a kWh/m²a kWh/m²a kWh/m²a kWh/m²a kWh/m²a GBP/m²a kg/m²a
Degree Days Heating (HDD): Cooling (CDD):
3372.35 588.28
Secondary Electricity
57
17 5
Heat Transfer Coefficients Building Shell Average: Floors: External: Underground: Openings:
[%]
[%] 78
88
78 88
Project Energy Balance Lighting and Equipment 2551.2 kWh/a
Added Latent Energy
Supplied Energy per Month
Human Heat Gain 1130.4 kWh/a
Service Hot-Water Heating
4000
1896.0 kWh/a
Solar Gain
2000
13845.7 kWh/a
Heating
Energy
CO2 Emission
Source Name
Fossil Secondary
272.6 kWh/a
6522.6
Energy Consumption by Sources Source Type
Fossil Natural Gas
5
5
General Project Data Project Name: City Location: Latitude: Longitude: Altitude: Climate Data Source: Evaluation Date:
Energy Sources
CO2 Emission 7
Natural Gas Electricity
Total:
Quantity
Primary
Cost
kWh/a
kWh/a
GBP/a
33906 2551
37297 7653
1695 357
7323 551
36458
44951
2052
7874
Jan. Feb. Mar. Apr. May. Jun.
Jul. Aug. Sep. Oct. Nov. Dec.
32010.8 kWh/a
0 [kWh] 0
Transmission
2000
Infiltration
46770.6 kWh/a
kg/a
3052.9 kWh/a
Sewage
4000
1896.0 kWh/a
6000 Energy Quantity 7
Emitted Energy per Month
Primary Energy
Thermal Blocks
17
Zones Assigned 14
Thermal Block 57
17 5
[%]
001 Pentir hir [%]
Total: 78
88
Residential
14
Source Type Fossil Secondary
Quantity by Source: Primary by Source:
Source Name Natural Gas Electricity
Total:
[kWh/a]0
36458
Volume m³ 461.66
171.88
461.66
Primary Energy kWh/a 37297 7653
CO2 emission kg/a 7323 551
44950
7874
44951 3/3
1/3
Gross Floor Area m² 171.88
Environmental Impact 83
93
Operation Profile
page 7/16
Outline Proposals
4 Retrofitting Methodology 4.1 Introduction The proposed retro fitting solution methodology needs to be practical and appropriate to the building typology, which is to a greater extent, influenced by the period of construction. It must therefore be based on a sound understanding of the existing construction, and its capability to support retrofitted materials and components. In this case the building fabric may is probably over 150 years old but heavily remodelled i the 1950s. Added to this probably in the mid 1990s is an extension constructed of cavity walls typical of that period. As reported elsewhere the condition of the fabric is good and capable of supporting the retro fitted technologies detailed in this section. The client has requested that we take the necessary steps to make the dwelling nett carbon neutral in terms of energy usage. However, this is the ideal scenario: if these steps require too many compromises aesthetically, or are too costly, the efficiency may be compromised. Obviously only the client can make the final decision on whether a compromise solution is needed, but it is considered that the recommendations given in this report answer the brief insofar as the practicality and costs are concerned. This section of the report is designed to explain the theoretical approach, and provide the client with sufficient insight to decide whether or not to implement the solutions recommended. It is important to realise that there is no one version of EEM which is correct and more sustainable than another: the solutuons offered in this report are based on the experience of the author, gathered over some 30 years of working in the sector.
page 8/16
4.2 Computer Modelling
4.3 Retrofit 'Recipe'
Following a measured survey the data is translated into a BIM model. Using Graphisoft Archicad the buildings are modelled precisely. This enable the designer to quantify the existing building and using the built in thermal modelling engine obtain a theoretical performance based on typical occupancy.
Balancing the available budget and achieving energy efficiency in the virtual dwelling is achieved by putting together a combination of retro fit technologies, as listed below. With experience it is possible to get a feel for the combination of measures needed to achieve the optimum outcome. Obviously the more modern the dwelling, the less onerous the interventions need to be. For a low rise dwelling the 'recipe' usually includes a combination of all or some of the following:
In this case the client was able to provide an annual energy summary for gas and electricity which allowed the author to adjust the data inputs to match as near as possible the figures reported in use. The assessment is provided on page 7 of this report. The data is then exported to a SAP calculator so that the current rating can be checked, but more importantly, to provide a base model which can be compared with subsequent iterations of the model as energy efficiency measures are proposed and 'tested'. The model can be viewed at important stages so that the effects of various interventions can be understood. Quantities can be extracted so that construction budgets can be allocated. In the case of prefabricated building elements like cladding and windows, the model can be used to co ordinate procurement.
● External wall insulation ● Additional roof insulation (either interstitial or over roofing) ● Perimeter insulation below dpc (since increasing the amount of floor insulation is usually not practicable) ● Replacement windows and external doors with emphasis on air tightness at reveals and opening sashes/leafs ● Installation of mechanical ventilation with heat recovery ● Replacement of existing heating boiler to disconnect the dwelling from the gas grid ● Replacement of hot water storage ● Treatment of thermal bridges eg at reveals, heads and cills ● Heating/DHW control simplicity It is important to understand that the recipe works only when installed as a complete package, but also when the occupants are included in the process: human behaviour has a significant effect on the performance of low energy dwellings, and although outside the scope of this report, education or training in the use of the controls and more fundamentally, how the building responds to outside conditions, should be included as part of the package to optimise the investment.
4.4 External Wall Insulation
4.5 Roof Insulation
4.6 Slab Perimeter Insulation
There are many EWI products and processes. Our preferred solution is Parex UK who have a network of authorised installers.
The dwelling currently has a traditional ventilated cold roof with insulating quilt at ceiling level. Whilst it is possible to increase this insulation in practice it is difficult and is likely to increase In s u l a t i o n condensation risk due to poor ventilation.
Since insulating the existing ground floor is impractical the easiest method of upgrading this thermal element is to insert perimeter insulation below dpc level. The depth of the insulation should be no less than 600mm, which effectively enables the ground bearing theCI/SfB slab to become a heat store.
Parex is a system of coatings which includes in its range smooth self coloured render. There is no need for preparation of the substrate and the insulation which can be of varying thicknesses to suit energy saving targets.
(27.9)
It is also difficult to remove cold bridging when the EWI does not 'meet' the insulation at eaves level. The best solution is to place the insulation layer outside the roof giving the whole house a warm envelope. Obviously this necessitates the removal of the existing roof covering and its replacement over the insulating layer.
We recommend a thickness of 100mm which will reduce U-values for the rubble walls from around 2.0 down to 0.25 W/m2K.
Twelfth Issue
Rn7
M2
September 2019
The example below illustrates the concept and the heat losses reduced as a result of the removal of this thermal bridge for thin walls however the principle is the same for thick masonry walls.
Since the client has also expressed a desire to remove the existing Since the client has expressed a preference to replace the existing unsightly concrete paving around the building there will be a concrete roof tiles with slate, it makes sense to take the consequential saving in the cost of this EEM. opportunity to place the insulation on boarding on the existing rafters as INSULATION indicated below. FOR TILED OR SLATED PITCHED WARM
K7 Pitched Roof Board
The illustrations below show the pump applied render coating, and an insulated reveal detail needed to prevent cold bridging at openings.
This is a non-contractual document. The information in this construction detail only constitutes suggestions and must be read in conjunction with the main project specification. This information in no way replaces the project specification. If you have any technical questions relating to this document please contact the Parex Technical department on 01827 711755 or send an email to enquiries@parex.co.uk.
24. Parex Corner Bead With Mesh. If required, fix the profile at a maximum of 300mm centres using non corrosive Firtree fixings.
22. Parex insulation Stop Bead profile. Profile width to suit insulation thickness. Fix the profile at a maximum of 300mm centres using non corrosive fixings. Shim the back of the profile to level and line along uneven surfaces.
18. Insert Parex EPDM seal and fully seal the void with silicone ensuring a complete seal is achieved in all instances. Clean off excess silicone to leave a neat finish.
13. PAREXTHERM Render Systems
13
24
b
22
or
18
ROOF SPACES The choice of slates will depend on aesthetics, longevity, and budget. We prefer natural stone slates and Welsh slates are high quality and locally available making them a sustainable choice. This is likely to be subject to more detailed cost analysis.
a
INSULATED REVEAL - ROBUST DETAIL
3
Decarbonising Pentir Hir Pentyrch
l
Premium performance rigid thermoset insulation – thermal conductivities as low as 0.020 W/m.K
l
Unaffected by air infiltration
l
Resistant to the passage of water vapour
l
Easy to handle and install
l
Ideal for new build and refurbishment
l
Non–deleterious material
l
Manufactured with a blowing agent that has zero ODP and low GWP
page 9/16
Outline Proposals
4.7 High Performance Doors and Windows There are many choices for low energy doors and windows. The key factors influencing choice would be: ● low U-value/well draught sealed ● provenence: select local manufacturers if possible ● materials: timber is a more sustainable material than aluminium but this needs to be balanced against maintenance ● cost ● aesthetics ● security: HA's normally require Secured By Design compliance Our preferred option is one of the ranges marketed by Green Building Store. They offer a range of different products but all are FSC chain of provenance, low emissivity triple glazed, providing very high energy efficiency. However the client has expressed a preference for retaining the 'Georgian style' timber casements already installed on the property. In our opinion this will compromise the low energy formula and lead to possible difficulties of cold bridging, condensation and mould growth.
We recommend, in order of preference: ● complete replacement with triple glazed units from Green Building Store or Rationel ● replacement with double glazed uPVC window which can be made with Georgian style subdivisions ● removal of existing windows and replacement at the external face of existing wall
page 10/16
4.8 MVHR and Air Tightness
4.9 Heat Pump
Mechanical ventilation with heat recovery is now becoming standard on low energy housing. MVHR systems work by combining supply and extract in one unit. Moisture-laden, stale air is extracted from ‘wet’ areas, such as kitchens and bathrooms.,The heat from this stale air is recovered via a heat exchanger, and this tempered air delivered into the living areas of the home.
The house is currently heated with an inadequate gas fired combi boiler which is a CO2 emitter. The client is committed to replacing this with a heat pump.
Retrofitting MVHR units in existing dwellings can be intrusive, as ductwork needs to be taken from the wet rooms back to the unit. If this is a barier to installation then a second best option would be for a positive pressure fan to be installed in the attic but this would compromise the energy efficiency of the dwelling. A prerequisite for installation is the reduction of air leakage from the dwelling. With attention to detail it should be possible to achieve less than 2ac @ 50Pa and this figure is assumed in the SAP calculations. Assuming MVHR can be installed our preferred choice would be by Nuaire, manufactured in S Wales, Nuaire’s MVHR range recovers heat at 95% efficiency, making it the most effective range currently available. In warmer months when cooling is required to maintain comfort levels, Nuaire’s MVHR Eco range offers 100% bypass with no loss of resistance.
GSHPs are relatively expensive due to the need for a borehole: there is unlikely to be sufficient space for a ground loop. A GSHP combined heating scheme may be feasible for this project especially as the RHI has been extended for another year and enables the spreading of cost over a long term. However, our preference is for an ASHP as the most economical and practical solution. The performance of ASHPs has improved and seasonal CoPs can now be expected to reach around 3.5. Since the client is keen to keep a log burner, it is likely that the HP will be used mainly for HW and for the coldest days in winter. We have no preferred choice of unit as it is likely to be based on factors we may not be aware of, eg, maintenance contract, economies of procurement, warranties etc.
Decarbonising Pentir Hir Pentyrch
4.10 Insulated HW Cylinder
4.11 Underfloor Heating
4.12 Secondary Heating
The dwelling is currently heated with a combi type boiler which provides hot water on demand. This is inadequate for a large dwelling especially when an additional bathroom is envisaged.
The boiler is to be replaced with a heat pump which supplies low temperature hot water for heating. The reduced heat requirement of the dwelling following improvements will be best delivered by means of underfloor heating. Our preferred supplier of UFH is Jupiter Systems.
The client is happy to remove the gas fire in the interests of sustainability (no fossil fuels) but is keen to keep a log burner in the house.
It is recommended that a well insulated stratified cylinder is installed at least 200l capacity. This will require space allocation and preferably near to the heat pump to reduce heat losses in connecting pipework.
The ground floor lis presumed to be parquet flooring on uninsulated concrete. For practical reasons the UFH build up needs to be low profile. The Jupiter EPS system will hopefully not present difficulties for the installer.
Our preferred supplier of this item is Wondrwall.
Log burners need to be carefully designed into the project as their performance in air tight Passivhaus type conversions can be problematic. There are now several manufacturers with stoves designed for use with MVHR but the choice will depend on aesthetics and physical dimensions of the fire place. We do not have recommendations for a particular type at this stage but blocking the chimneys, removing open fireplaces and direct air feeds will be necessary to maintain the air tightness required. It may be a good idea to specify a type with back boiler as this could further improve efficiencies for DHW production.
The upper floor is suspended timber with traditional floorboards. The client has already indicated that these are to be removed in certain areas. The insertion of the Jupiter Neo system should present few difficulties and allow the distribution of heat to the upper floor.
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Outline Proposals
4.13 Smart Controls and Metering
4.14 PV cells
4.15 Battery and Inverter
Experience in new build housing tells us that simple controls are an essential part of the solution. The installation as far as possible needs to be 'fit and forget', in other words, as few interventions by the occupants as possible shoud be required.
PV cells are generally the best way to generate on site renewable energy. When combined with smart metering and controls, they are able to supply electric current to the grid, to the dwelling for instantaneous use, and even directly to the DHW to offset costs associated with running the heat pump.
Latest innovations in energy efficiency include the use of an in house battery which, when linked to an inverter, a pv array, and a smart meter, allow the controls to ascertain the optimum balance between supply, distribution or storage of onsite renewables.
The best form of Smart controls are therefore those which are discreet in appearance, and 'learn' how best to control the heating based on weather observation, but also on the behaviour of the occupants. Since the house is to be completely rewired, it makes sense to use a system which has sensors in each room. For this reason our preferred supplier is Wondrwall.
The Wondrwall system does not just control the heating: it can be configured to control lighting and ventilation, which also enables humidity control. Wondrwall recommend that the supplier is Octopus as this optomises the sustainable supply of power through a Smart meter. If solar pvs are installed as recommended the use of a smart conrol can also help the installation to allocate renewable pwer generation and even store energy in the hot water tank, something which may be useful during summer when heating is not normally required.
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The costs associated with installing pvs are reducing annually, and the efficiencies of converting sunlight to energy are increasing. Even though the government have now removed feed in tarriffs for new installations, they are a good way to increase efficiencies so long as the fabric first approach has been taken. The size of the array needs to be balanced against the requirements of the dwelling to ensure best cost effectiveness.
Wondrwall have introduced a complete system of integrating all three devices using smart controls to optimise electrically operated heating systems. Tesla Powerwall is another market leader and it is possible to link the dwelling supply system to the battery which drives an electric car. This topic can become very complex and specification of the system is outside the scope of this report: however, for completeness, it would be incorrect not to include these technologies as part of the summary of improvements.
Decarbonising Pentir Hir Pentyrch
4.16 Rainwater Harvesting
4.17 Greywater Harvesting
Rainwater harvesting (RWH), whilst doing nothing to make a house more energy efficient, is certainly another way of making it more sustainable, by reusing a plentiful and renewable resource.
The client expressed a desire to install greywater harvesting. This re uses waste water from showers, baths, basins and washing machines and needs to be collected, filterd, stored and disinfected.
It is outside the scope of this report to discuss the implications of RWH on the national infrastructure, and it is for the client to decide what level of installation is appropriate.
The site is appropriate for the installation of a large below ground tank, which is the best way of storing water for long periods: above ground tanks tend to allow water to stagnate. If the use of recovered water is solely for the garden, an above ground system may suffice, and is relatively low cost.
The equipment needs to be maintained and cleaned at regular intervals to ensure good outputs. In the opinion of the author, the cost of the installation is unlikely to be offset by savings from the low water usage in the household.
If the recycled water is to be used for other purposes such as wcs, washing machines a below ground tank is required, along with the pumping infrastructure and 'double plumbing'.
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Outline Proposals
5 Proposals
Following proposed Retrofit works SAP Box Reference (Calculation of EPC COSTS, EMISSIONS AND PRIMARY ENERGY Section) [98] [64] [231]
5.1 Summary of Brief
5.2 SAP Calculations
The following is a list of works envisaged, split into five categories. The list is not intended to suggest that all items are necessary for a satisfactory retrofit project and some items clearly fall onto the category of 'wishlist'.
The data obtained from the BIM model was fed into the SAP tool by Constructive Thinking registered SAP assessors.The table right summarises the results:
Demolition work : ● removal of roof tiles, rainwater goods, and all projections such as fascias ● excavation of perimeter footpaths ● removal of windows and external doors and frames ● removal of boiler and flue, HW calorifier
This rating could be improved by the addition of solar PVs and in theory carbon zero space heating could be achieved. A [4] 8kW array would give a SAP rating of 104A and this is assumed in the conclusion.
Construction Phase (EEMs only): ● EWI ● Over roofing and insulating ● Window/external door replacement ● MVHR ● ASHP ● Buffer tank ● DHW tank ● UFH to lower and upper floors ● solar voltaic cells (PVs) ● Smart controls ● Floor finishes ● Air pressure testing ● Enclosure for tech equipment
For reference PassivHaus standard is 15kWh/m2/a
Making Good Work/Optional Extras ● flooring ● refixing rw gutters etc ● redecoration ● rewiring ● replumbing External Works ● paving external apron ● new driveway surface ● rw harvesting and tankage ● works to garage New Extension ● complete package
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5.3 Caveats It is assumed that a level of air tightness can be achieved and will need to be verified on site with air pressure testing. This is an aspirational level which is achievable but requires attention to detail and good workmanship. The limitations of the software: [36] assumptions relating to thermal sum[38]/12 bridging have been made which can be refined by modelling (outside the scope of this report). The technical room spatial requirements cannot be met without creating a new space or altering an existing one: it is recommended that all equipment is located inside the heated envelope.
kWh/a demand
Space Heating Demand Domestic Hot Water Ventilation Small Power Standing Charge Gas Standing Charge Electric
10224 2481 645
Micro Generation (PV) Thermal Storage Battery Solar Thermal Floor Area Totals value/m2/a
8000
Efficiency of Unit
Utility Used by Unit
kWh/a required to meet demand
2.5 Electricity 2.5 Electricity 1.25 Electricity Electricity
Cost (SAP 9)
4090 992 516
£777.05 £188.53 £98.04
2122.56 514.99 267.80
£0.00 £90.00 1 Electricity Electricity Electricity Electricity
8000
£613.46 £148.84 £77.40
556.20 134.95 70.18
£0.00 £90.00 -4152.00
220.55 13598
£1,153.62
-1246.64
£929.70
761.33
19
£5.23
-5.65
£4.22
3.45
[98]/[4]
Net kWh Max Import
compare PassivHaus Heat Loss (W/K)
Name of Element
CO2 (SAP CO2 (SAP Cost (SAP 10) 9) 10)
% % of Total Improvement
Description of Measure
External Doors
3.77
1.43%
56.00% A-Rated Replacement
Windows
40.47
15.31%
31.81% A-Rated Replacement
Rooflights Ground Floor Slab Stone Wall Main Roof Vaulted Roof
1.52 53.44 50.07 13.85 1.20
0.58% 20.22% 18.94% 5.24% 0.45%
40.89% 25.00% 86.54% 48.00% 82.81%
Thermal Bridging Ventilation Loss
38.96 61.07
14.74% 23.10%
50.19% Improve detailing to ACD std 69.22% Improve air tightness
Total
264.3349
●
Ventilation Loss Calculation Jan 63.2754 Feb 61.6498 Mar 30.6242 Apr 57.5311 May 57.0892 Jun 55.3218 Jul 54.438 Aug 54.438 Sept 56.6474 Oct 59.7404 Nov 61.066 Dec 61.066 Total 672.8873 Average 56.073942
A-Rated Replacement 100mm Below Damp Insulation 100mm EWI 200mm rafter level insulation 200mm rafter level insulation
Calculated Input Value or Assumed 1.1 Measured 1.2 Measured 1.2 0.45 0.28 0.13 0.11
Source of Data Manufacturer/ Specification Manufacturer/ Specification Manufacturer/ Specification U-Value U-Value U-Value U-Value
Measured Calculated Calculated Calculated Calculated <select> <select> <select> <select> <select> 0.086 Assumed Design Target 2 @ q50 Assumed Design Target
Decarbonising Pentir Hir Pentyrch
6 Conclusion 6.1 Predicted Energy Rating
6.2 Costings
The draft certificate below indicates the result of the SAP assessment if the dwelling is given the full range of retrofitted technologies described in this report.
The table indicates the costs associated with the various retrofit measures recommended.
The predicted energy rating is 101 which is effectively carbon neutral. The calculation takes into account the energy collected by the pv array. The building would be nett carbon neutral which means that over a typical year the energy required to heat the building would be met by the energy collected.
PREDICTED ENERGY ASSESSMENT
Dwelling type: Date of assessment: Produced by: Total floor area:
House, Detached 23/11/2020 Constructive Thinking Studio Limited 220.55 m²
T
This document is a Predicted Energy Assessment for properties marketed when they are incomplete. It includes a predicted energy rating which might not represent the final energy rating of the property on completion. Once the property is completed, this rating will be updated and an official Energy Performance Certificate will be created for the property. This will include more detailed information about the energy performance of the completed property.
Significant differences not taken into account in the table relate to: Financing: no allowance has been made for offsetting cost of HP with the RHI HP: ASHP could reduce figure by £15k New build: no account taken in costings for additional space requirements or enclosure for plant VAT: a lower rate is potentially applicable to energy saving measures Costs exclude fees, statutory fees, preliminaries NOTE: All figures subject to tender and contractual terms. The inclusion of costings does not imply that the goods or services described are oofered by the author of the report and are for project planning purposes only.
AF
(92 plus)
A
(81-91) (69-80) (55-68) (39-54)
(92 plus)
A
(69-80)
D
(55-68)
E
(39-54)
F
(1-20)
G
Not energy efficient - higher running costs
Wales
Very environmentally friendly - lower CO 2 emissions
(81-91)
C
DR
(21-38)
B
101
EU Directive 2002/91/EC
The energy efficiency rating is a measure of the overall efficiency of a home. The higher the rating the more energy efficient the home is and the lower the fuel bills are likely to be.
(21-38) (1-20)
A
B
101
B
C
D E F G
Not environmentally friendly - higher CO 2 emissions
EU Directive 2002/91/EC
Wales
The environmental impact rating is a measure of a home's impact on the environment in terms of carbon dioxide (CO 2 ) emissions. The higher the rating the less impact it has on the environment.
However, it was not possible during the preparation of the report to arrive at a satisfactory design solution for spatial improvements, and the kitchen/bathroom fit out and and external works costs have been omitted at this stage. A further iteration of this report may well include these omissions but this will be a future decision for the client.
Maintenance Rewiring Replumbing Redecorate New floor finishes
5000 4000 5000 6000
£30/m2
Energy Efficiency Retrofit EWI Reroofing New double glazing Thermal bridging MVHR GS Heat pump/boreholes UFH install DHW tank Controls PV array 8kW
20000 32000 30000 7500 6000 30000 28000 2000 5000 10000
Parex Estimate Vellacine Estimate Estimate Estimate Jupiter Jupiter Jupiter estimate
Based on £60/m2
170500 190500 C
This report has not been submi ed through the Elmhurst Energy members’ portal, therefore results are subject to change when the dwelling is completed.
Page 1 of 1
It has been shown that the available budget is sufficient to make the dwelling effectively carbon neutral, and there is also some leeway in the specification for savings which may allow other 'lifestyle' works to be carried out inside the budget figure.
20000
Environmental Impact (CO 2 ) Rating
Very energy efficient - lower running costs
With this report the author has assessed the dwelling and its suitability for deep retrofitting and energy efficiency measures; clarified where possible the requirements of the client's brief and budget; selected appropriate EEMs; and carried out a series of calculations to fine tune the result so that there is an optimum cost benefit to carrying out the works.
Pentir Hir Budget Estimate
The energy performance has been assessed using the Government approved SAP2012 methodology and is rated in terms of the energy use per square meter of floor area; the energy efficiency is based on fuel costs and the environmental impact is based on carbon dioxide (CO 2 ) emissions.
Energy Efficiency Rating
6.3 Conclusion
Regs Region: Wales Elmhurst Energy Systems SAP2012 Calculator (Design System) version 4.10r08
New Build Demolitions First floor extension Ground floor extension Renew bathroom Refit kitchen
10000 25000 30000 6000 25000
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Gillard Associates Ltd The Quaypad Cardiff Marina Watkiss Way Cardiff CF11 0SY T: +44 (0) 2920 229 133