The Great British Refurb: The energy efficient
refurbishment of the existing housing stock
Tadj Oreszczyn
UCL Energy Institute
University College London
12.5° C
12
11
S P 01
10
9
8
7
7.0° C
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
What are the options?
http://www.eco-hometec.co.uk/Ground%20Source%20Heat%20Pumps.htm
Reducing heat loss
http://www.whispertech.co.nz/content/library/WTL026Brochure.pdf
Efficient heating cooling and energy generation
PROBLEM SOLVED ?
Camden Victorian Low Carbon
Refurbishment 80% carbon
reduction (Code Level 4)
Code Level 6 (Zero Carbon) new
house Barratt’s Greenhouse
Zero Carbon House, Code Level 6 (2008)
Superinsulated Houses (1985)
http://www.thimkagain.co.uk/mk/past-projects.htm
http://www.bsjonline.co.uk/Journals/Builder_Group/B
uilding_Services_Journal/July_2007/attachments/Dia
gram.pdf
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 sociotechnical 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
30000
25000
y = -75.102x + 167672
R2 = 0.4126
kWh per year
20000
15000
10000
5000
0
1920
1930
1940
1950
1960
1970
1980
1990
Mean Year of Construction
2000
2010
2020
2030
Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling
30000
25000
y = -75.102x + 167672
R2 = 0.4126
kWh per year
20000
15000
10000
5000
0
1920
1930
1940
1950
1960
1970
1980
1990
Mean Year of Construction
2000
2010
2020
2030
Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling
30000
25000
y = -75.102x + 167672
R2 = 0.4126
kWh per year
20000
15000
10000
zero carbon for all
energy
5000
0
1920
1930
1940
1950
1960
1970
1980
1990
Mean Year of Construction
2000
2010
2020
2030
Postcode Sector Average Dwelling Age vs Average Gas Consumption per Dwelling
30000
25000
y = -75.102x + 167672
R2 = 0.4126
kWh per year
20000
The Great British Refurb 2030
15000
10000
5000
zero carbon for all
energy
0
1920
1930
1940
1950
1960
1970
1980
1990
Mean Year of Construction
2000
2010
2020
2030
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%!
‘In theory,
theory and practice are the same,
but in practice,
Santa Fe Institute in Factor Four
they’re not’
Why is theory and practice not the same in this
case ?
1. Applied physics wrongly
2. Not built/refurbished as modelled/theory
3. Do not understand changes in occupant
behaviour
PHYSICS APPLIED INCORRECTLY:
COMPARISON OF AIR INFILTRATION RATE PRE- AND POST-WARM FRONT
Pre-Warm Front
Post-Warm Front
WF 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%
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)
Health and the Great British Refurb
Before the refurb
• 20,000 excess winter deaths,
• 4,000 excess summer (2003)
• 40 per annum from carbon monoxide
• Mould and dust mites
After 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:
• This revision of the 1974 statutory
HMSO, 1984
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 future
IEA Technologies Perspective 2008
Energy efficiency 49%
MK 1990 – MK 2006 Energy Usage by Fuel at Text 5°C
Electricity
+70%
160
35
140
30
120
25
100
20
kWh
kWh
Gas
80
15
60
10
40
5
20
0
0
All
Low
Mid
1990 2006
High
All
Low
Mid
1990 2006
High
THANK YOU
Further practical information
• Sustainable Energy Academy-Old
home SuperHomes
http://www.sustainableenergyacademy.org.uk/index.php
• Low Energy Victorian House
http://www.levh.org.uk/
• Energy Saving Trust
http://www.energysavingtrust.org.uk/
Every little helps ?
LESS ENERGY
NO REBOUND
MORE ENERGY EFFICIENT
Every little helps ?
LESS ENERGY
WITH REBOUND
MORE ENERGY EFFICIENT
Every little helps ?
LESS ENERGY
WELL HEATED
NO REBOUND
MORE ENERGY EFFICIENT