67 Temple Avenue

The reality of energy savings in retrofit

Owen Daggett 25th September 2012

Role of Joseph Rowntree Foundation

Search: causes of

social problems

Demonstrate: solutions

Influence: policy and practice

POVERTY:To identify the root causes of poverty and injustice

PLACE:To support resilient communities where people thrive

AGEING SOCIETY:To respond positively to the opportunities and challenges of an ageing society

OU

R W

OR

K T

HE

ME

S

• Climate Change and Social Justice programme• Low/Zero Carbon Housing/buildings in practice

Recent and ongoing projects:

• Elm Tree Mews, New Earswick• Temple Avenue Project (Newbuild and Existing), York• Dormary Court, New Earswick• Derwenthorpe, York

JRF Search, JRHT Demonstrate & Influence

The Challenge?

The Vision for

New Earswick

An Economically

and Socially

Sustainable

Mixed

Income

Community – but

Not

Environmentally

The Refurbishment Strategy

Step 1

• Fabric Improvements

Step 2

• Heating & ventilation system improvements

Step 3

• Measures to reduce cost of hot water and energy use

The Starting Point

• Insert p6

Existing Condition- Modelled Performance

Predicted Fuel Costs per Year(August 2009)Heating £612

Hot water £136

Lighting £55

Observation and Testing

Thermograms: display surface temperatures in range of colours. Can show comparative heat loss through different elements.

Air Pressurisation testing: measures permeability of building envelope to determine air tightness. Can detect leaks and air infiltration.

Co-heating testing: measures whole house heat loss (fabric + ventilation). Calculates daily heat input which provides heat loss coefficient

Heat flux sensors: measure rate of heat loss through a material to give a “real” U-value

Boroscope investigation: remote video inspection used to view building fabric voids.

Understanding the performance of the fabric

Existing Condition- Actual Performance

Measured Heat Loss324.7 W/k

Predicted Heat Loss 341.4W/k

Measured air tightness 15.76m3(h.m2)@50Pa

Leeds Met carried out measured survey, visual inspection with air pressurisation, and full SAP.

Predicted thermal performance was reasonably accurate- but underestimated performance of the dwelling.

Inaccuracies existed in the original heat loss prediction due to an incomplete knowledge of the existing building

RDSAP would not have picked up these details

Standard Retrofit works

Decent Homes…..Plus

Standard Retrofit- Actual Performance

Predicted Heat Loss Reduction

102.8 W/k

Measured Heat Loss Reduction75.5 W/k

Measured air tightness 9.83m3/(h.m2)@50Pa

Why the underperformance?

CWI not installed properly, or cavity “bridged”

CWI U-values not achieved: predicted target 0.45 actual target 0.70

Loft insulation at incorrect depth and not extending to eaves

Thermal bypass in chimney- even though blocked as airtightness measure

Radical Retrofit worksAiming for an 80% CO2 reduction

Radical Retrofit- Actual Performance

Predicted Heat Loss Reduction

234.3 W/k

Measured Heat Loss Reduction165.7 W/k

Measured air tightness 5.42m3/(h.m2)@50Pa

Performance issues

Air tightness achieved (5m3/(h.m2)@50Pa

Triple glazed windows achieved claimed U-value (0.5W/m2k)

Solid floor insulation achieved claimed U-value (0.195W/m2k)

EWI failed to meet target U-Value (0.24 compared to 0.15)

How successful were the improvements?

73%OF PREDICTED

IMPROVEMENT

STANDARD RETROFIT

71%OF PREDICTED

IMPROVEMENT

RADICAL RETROFIT

How successful were the improvements?

• Project only tested the performance of “fabric” improvements- services is a POE project

• Existing house predicted performance was dependent on accuracy of initial survey- more intrusive survey may have minimised the gap

• Predicted improvements dependent on accuracy of data entered into software. E.g., CWI uneven filling resulted in U-value gap, but after rectification a gap still existed.

• Second stage works- similar to first stage, but for EWI- discontinuities difficult to avoid around doors and entrance

32% 69 Temple Avenue

How much did it cost?

£400 CWI

£550SEAL

CHIMNEY

£800

LOFT INSULATION

£3,000

AIRTIGHTNESS

£3,500

HEATING AND HOT WATER

£4,000INSULATION

AROUND GARAGE

£6,000REWIRE AND REPLASTER

£18,250STANDARD RETROFIT

£2,000

AIRTIGHTNESS

£5,000MVHR

£5,500SOLAR HOT

WATER

£6,000UNDERFLOOR INSULATION

£9,250EWI

£10,000DOORS AND WINDOWS

£37,750RADICAL RETROFIT

TOTAL NET PROJECT COST

£56k

Findings and Recommendations

Government & Regulators• If “as-built” performance does not meet design predictions, then the

Golden Rule is at risk of being broken• Green Deal assessment must consider “as-built” performance and

include tolerances in calculations of expected savings

Installers• Forensic observation and/or in-production testing should be used to

check CWI and other measures have been installed correctly• Education and training is needed to replicate experience and

knowledge

Considering the impact of the Green Deal

Findings and Recommendations

Asset Managers and residents

• Commission a comprehensive survey of the house and any alterations or replacement fittings before undertaking any improvement work;

• Consider capital and revenue cost, carbon cost effectiveness and level of disruption of potential improvements

• Seek professional advice

Considering the impact of the Green Deal

QUESTIONS, COMMENTS & OPINIONS?

Owen Daggett

Sustainability Manager

Joseph Rowntree Foundation

01904 615920

Owen.daggett@jrf.org.uk

@OwenDaggett

www.jrf.org.uk