The holistic approach for retrofit of buildings

Dr David Tetlow

Content 1.

Defining the problem and why retrofit is so important

The current retrofit approach – its drivers and limitations

•

Overview of factors that affect its uptake

•

Example cases

The holistic retrofit approach – its innovation over the existing system •

The rationale

•

Step by Step

Comparison of approaches and future challenges

There’s a global PROBLEM…..

Climate Change â€“ The International problem

60% reduction of 1990 Carbon Equivalent emissions by 2050

What is the UK’s Progress? 12

The majority of emissions from these are from

Emissions (MtCO2e)

Down 28%

buildings

Down 15% 6

0 Year

779 MtCO2e (1990) → 581 MtCO2e (2012) We’re doing… OK… sort of…

Little room to improve

Thereâ€™s a big Challenge Existing Buildingsâ€Ś UK 2050 required Average Rating

Exist Today Yet to build

The facts of 2050 ~6 million solid walled dwellings... ... Of a ~26 million total

Actual UK average rating?....

MILLIONS to Retrofit

RETROFITâ€¦..

Home energy retrofit is done to solve a Problem… Acute problems – Immediate Action Old lowefficiency central heating

Leaks in building structure requiring repair

Chronic problems – Limited Action Cold & poorly maintained external walls

Old & leaking windows

Level of action is dependant on peoples’ perceptions & considerations

The financial reality Zero Use

Target Use 80% Saving

Renewables (PV, Heat Pumps, etc) Mech ventilation + Heat recovery Energy Storage (PCM, Hydrogen, etc) ............ ~£300 + install cost per 1% saved energy ….. ?

Current Use

M5M3Energy M3

Usage M2 M1

High Resistance Windows

Solid Wall Insulation

~£275 install cost per 1% saved energy

~£200 install cost per 1% saved energy

M2 M1

Loft Insulation &/or Boiler upgrade

Low energy lighting

<£50 install cost per 1% saved energy

What is the best solution & how do we choose?...

(RdSAP) The current assessment method

4-6 weeks

< 24 Hours Building Survey

Pre-Retrofit Analysis

Dimensions, Location, Site, Constructions, Services, Layout, Air Tightness, Appliances

RdSAP Calculation Process Retrofit Recommendations + Possible Savings

Many Assumptions made

Retrofit Actions Taken… …Leading to £££s Spent & Savings?...... ….You Assume….

Face Value Acceptance..

Ass-U-Me

…& Risk of Losses

Assumptions using fixed condition data....

Based on who using the house?

A very large ranges of cost, & very narrow typical savings...

What is the best solution??? Starting at a score of 58

(Dowson, Poole et al. Energy Policy 2012)

Is this one size fits all approach common sense?.â€Ś.

Case examplesâ€¦..

The UK HERB houses

Te r

ra ce

UK Stock

-D Sem i

Ter rac es

Two Terrace & Four Semi-detached

Semidetached

ProďŹ le of the UK Housing stock by age and type (Dowson, Poole et al. 2012)

UK majority built in this 100 year period

HERB UK house surveys As Built

Year 1900s

Characteristics Solid fuel Single glazing No wall insulation No loft insulation No floor insulation

Current

2013

Change of fuel & boiler change (possibly A rated) Double glazing CWI/EWI/IWI 270mm mineral quilt loft insulation Floor insulation Low energy lighting (CFLs)

1      

2      

Y N N 200 N 38%

Y Y N 300 N 13%

PROPERTY 3 4             Y Y N 170 N 71%

Y Y N 300 N 13%

5      

6      

Y N N 200 N 67%

Y Y N 160 N 88%

Why?

Government subsidies and imposed energy legislation

However: Cross Solution Impacts… …Some examples

Example 1 – Static Solutions - Windows

s Built

Year 1900s

Characteristics Solid fuel Single glazing No wall insulation No loft insulation No floor insulation

urrent

2013

Change of fuel & boiler change (possibly A rated) Double glazing CWI/EWI/IWI 270mm mineral quilt loft insulation Floor insulation Low energy lighting (CFLs)

1      

2      

Y N N 200 N 38%

Y Y N 300 N 13%

PROPERTY 3 4             Y Y N 170 N 71%

Y Y N 300 N 13%

5      

6      

Y N N 200 N 67%

Y Y N 160 N 88%

A Modern solution for a traditionally constructed building

WHY? Repairing or upgrading weather worn building materials

Old rotten wooden windows are replaced with modern uPVC efficient versions due to Necessity ~ÂŁ3000-5000

Discomfort….

Structural Problems….

Loss of

Example 2 – Active solutions – Boiler Replacements PROPERTY

As Built

Year 1900s

Characteristics Solid fuel Single glazing No wall insulation No loft insulation No floor insulation

Current

2013

Change of fuel & boiler change (possibly A rated) Double glazing CWI/EWI/IWI 270mm mineral quilt loft insulation Floor insulation Low energy lighting (CFLs)

1      

2      

3      

4      

5      

6      

Y N N 200 N 38%

Y Y N 300 N 13%

Y Y N 170 N 71%

Y Y N 300 N 13%

Y N N 200 N 67%

Y Y N 160 N 88%

20-25kW Heating load

3-6kW Heating load

Loss of Further

(1) Boiler upgrade

(2) Insulation of external walls (Â£7000-12000)

Boiler Oversized = Loss of efficiency

Consequences of cross-solution impact £££

M3 Usage LOSSM5M3Energy M2 M1 M6

££ Load requirement to improve Internal comfort = Loss of efficiency

M2 M1

How to avoid cross solution impact?... â€ŚApproach the problem in Context.

(1) Building dimensions

(2) Climate

(3) Building type (5) Building Services (7) Building Site Impacts (9) Appliances (11) Energy Prices (13) ……….

(4) Building Orientation (6) Environmental Controls (8) Occupant behaviour (10) Primary Energy Sources (12) Occupant Preferences

Analyse the system as a Whole – hence holistic

6-12 Months Building Survey Dimensions, Location, Site, Constructions, Services, Layout, Air Tightness, Appliances

4-6 weeks Pre-Post Retrofit Analysis

Energy Simulations

6-12 Months Physical Monitoring

Retrofit Plan + Actions

Mains Gas, Mains Electric, Appliances, Climate, Temperature, Humidity, Luminance

Physical Monitoring

Subjective Monitoring

Mains Gas, Mains Electric, Climate, Temperature, Humidity, Luminance

Appliance usage, Heating usage, Comfort Perception, General Wellbeing

Comfort Simulations

Economic Analysis

Subjective Monitoring Appliance usage, Heating usage, Cooking, Comfort Perception, General Wellbeing

Retrofit Technology Solution Library

Accuracy Feedback Analysis + System Update

ROI Survey Gas & Electric Savings, Renewables Income, Resident Comfort & Wellbeing

Comparison?....

• • • • •

Existing Method

Holistic Method

Advantages

Quick, Based on Solid-Science (i.e. the BRE), Government Approved, Low Cost, Can be applied to large scale developments when funding is available.

• • • • • • • •

Disadvantages

Disadvantages • • • • • • • • •

Uses many Assumptions, Science used is limited, Bases calculations on Abstract Data, Open to Human Error, Provides only Typical Savings, Gives no sense of certainty to resident, No recognition of Cross-Solution Impact, Subjective feedback used for its updates , Resident financial commitment based on faith.

Based on measured Physical Data, Accurate, Gives a range of solutions for resident needs, Aims to improve Wellbeing of residents, Flexible to changing economic conditions, Evolves using physical data feedback , Provides Certainty for investment, Makes the industry more Accountable.

• • • • • • •

Underdeveloped Requires time-investment, Currently is expensive, Requires technology development, Requires software development, Has not been proven to function, Requires use of sensitive data.

So whereâ€™s this going?....

Sensors can be expensive

Method for subjective data collection requires development

Communication is manual â€“ requires automation

Data for economic analysis manually imported â€“ requires automation

5 2 3

5 Methods for testing innovations in holistic

integration require development

2015

1990

25 Years

It is 35 years to 2050, the problems listed should be resolvable based on our history