The Great British Refurb: The energy efficient refurbishment of the existing housing stock

Tadj OreszczynUCL Energy Institute University College London

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Existing domestic buildings are key to tackling climate change • “Worldwide, 30-40% of all primary energy is used in buildings.” “In Europe,

buildings account for 40-45% of energy consumption in society“, UNEP 2007• the Climate Change Bill mandates an 80% reduction in UK’s CO2 emissions

by 2050• UK domestic homes responsible for 27% of the UK’s GHG emissions, • 80% of this is for space and water heating.• 70% of UK homes will still be here in 2050• Need energy efficient buildings for other reasons:

– Comfort and health – fuel poverty– Security of energy supply

Reducing heat loss Efficient heating cooling and energy generation

http://www.whispertech.co.nz/content/library/WTL026Brochure.pdfhttp://www.eco-hometec.co.uk/Ground%20Source%20Heat%20Pumps.htm

What are the options?

Code Level 6 (Zero Carbon) new house Barratt’s Greenhouse

Camden Victorian Low Carbon Refurbishment 80% carbon reduction (Code Level 4)

PROBLEM SOLVED ?

http://www.bsjonline.co.uk/Journals/Builder_Group/Building_Services_Journal/July_2007/attachments/Diagram.pdf

http://www.thimkagain.co.uk/mk/past-projects.htm

Superinsulated Houses (1985)

Zero Carbon House, Code Level 6 (2008)

23 years

The challenge: How to deploy appropriate technology to 24 million dwellings within a complex socio-economic system to reduce carbon emissions by 80% - The Great British Refurb

• We have more evidence than we need that technology alone will not deliver

• Technology can play a significant part in the solution or the problem. A schematic representation of the inter-relationships between occupant behaviour and other factors in influencing energy use in domestic buildings.

Energy usage and occupant behaviour:understanding socio-technical interactions, Summerfield 2008

Why do we find energy use in buildings difficult?• Energy is used in complex

ways, see diagram• Difficult to measure and

interpret-– Fuel bills are erratic and difficult to

interpret– Everything changes e.g. climate– Fuel prices have dropped in real

terms and relative to other items (3% for 2000 to 2006 of household expenditure – half of 1980).

Average UK house powered by humans

£400,000 per annum minimum wage

The Great British Refurb:

Government Heat consultation 2009 ‘our aim is that by 2030 all homes and other buildings will have received a ‘whole-house’ package of measures that covers all of the cost-effective energy efficiency measures available for that property at the time, as well as renewable heat and electricity measures needed to meet our renewable energy aims. ‘ The greatest engineering challenge this century?

Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling

y = -75.102x + 167672R2 = 0.4126

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Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling

y = -75.102x + 167672R2 = 0.4126

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Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling

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zero carbon for all energy

Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling

y = -75.102x + 167672R2 = 0.4126

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The Great British Refurb 2030

zero carbon for all energy

What is Warm Front ?

• Targeted at vulnerable (elderly and young) fuel poor • In 2007/8, Warm Front received £350 million funding,

allowing the Scheme to assist almost 270,000 households;

Warm Front

• Increases temperature in living and bedrooms• Improves comfort• Reduces fuel cost• Reduces mould• As a consequence it improves mental health and should

reduce winter deaths• But what does it do to energy use?

Mean energy use rises by 34%!

Why is theory and practice not the same in this case ?

1. Applied physics wrongly2. Not built/refurbished as modelled/theory3. Do not understand changes in occupant

behaviour

‘In theory, theory and practice are the same,but in practice, they’re not’ Santa Fe Institute in Factor Four

Pre-Warm Front Post-Warm FrontWF Scheme N Infiltration rate

(m3/hr/m2) N Infiltration rate(m3/hr/m2) % Change

All properties 78 17.7 (s.d. 7.1) 143 17.0 (s.d. 7.2) -4%

w/o CH 22 19.1 (s.d. 7.8) 51 16.5 (s.d. 7.3) -14%

w/ CH 56 17.1 (s.d. 6.8) 92 17.2 (s.d. 7.2) +1%

PHYSICS APPLIED INCORRECTLY:COMPARISON OF AIR INFILTRATION RATE PRE- AND POST-WARM FRONT

Stamford Brook – thermal envelope defects – convective bypasses(Lowe et al 2007)

Not refurbished as modelled/theory 20% cavity wall missing in insulation (n = 85)13% loft area missing in insulation (n = 85)

Stamford Brook – thermal envelope defects(www.leedsmet.ac.uk/as/cebe/projects/stamford/summary.htm)

Changes in occupant behaviour

• Benefit of insulation taken as increased thermal comfort and not reduction in energy use - “Rebound effect”, “Take Back”, “Comfort Factor”, “Take off”

• People interact with complex systems in complex ways

Theoretical boiler efficiency is not being achieved

“…very high proportion of tenants (80%) used some combination of gas fire and central heating.”

(Energy efficient modernisation of housing: a UK case study, Bell, Lowe, 2000)

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Health and the Great British RefurbBefore the refurb• 20,000 excess winter deaths,• 4,000 excess summer (2003)• 40 per annum from carbon monoxide• Mould and dust mitesAfter the refurb (depends on occupant behaviour)• Reduced CO and winter excess• Summer deaths may increase unless we take care• Dust mites could increase if we do not take care• Need to reduce other sources of pollution - formaldehyde

The Great British Refurb:• Essential – big changes• The greatest engineering challenge this century• Will not be easy or cheap – but cheaper and easier than alternatives• Requires socio-technical advances• Real verification (smart meters, Domestic MOT, etc)• Major and rapid changes in research, education, supply chains,

contracting, etc • Development of a ~ £10 billion per annum refurb industry• Care in terms of future changes to health and impact of climate change • Must go hand in hand with other policies to achieve target reductions

in emissions, e.g. Rise in fuel prices, regulation, decarbonisation of supply ,etc.

Fuel and Electricity (Heating) (Control) (Amendment) Order 1980, SI 1013, London: HMSO, 1984 • This revision of the 1974 statutory

instrument lowered the maximum heating limit to 19ºC and it applies with certain exemptions to all buildings not used for living accommodation.  Buildings affected by the new limit include public buildings. This Order allows the temperature in one part of a building to exceed the maximum limit if this is a necessary consequence of ensuring that the temperature throughout the building exceeds the appropriate statutory minimum.

Energy futureIEA Technologies Perspective 2008

Energy efficiency 49%

MK 1990 – MK 2006 Energy Usage by Fuel at Text 5°CGas

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THANK YOU

Further practical information

• Sustainable Energy Academy-Old home SuperHomes http://www.sustainable-energyacademy.org.uk/index.php

• Low Energy Victorian House http://www.levh.org.uk/

• Energy Saving Trust http://www.energysavingtrust.org.uk/

MORE ENERGY EFFICIENT

LESS ENERGY

NO REBOUND

Every little helps ?

MORE ENERGY EFFICIENT

LESS ENERGY

WITH REBOUND

Every little helps ?

MORE ENERGY EFFICIENT

LESS ENERGY

WELL HEATED NO REBOUND

Every little helps ?