Memorandum submitted by English Heritage
INTRODUCTION
English Heritage welcomes the decision of the
Communities and Local Government (CLG) Committee to examine the
contribution which the existing housing stock makes to UK carbon
emissions. This is an opportunity to demonstrate that the stock
of existing traditional buildings can be adapted sympathetically
to contribute to the overall reduction of carbon emissions from
England's housing stock. English Heritage is keen to use our practical
knowledge and expertise of how older housing behaves to help people
understand how to make adaptations which respond to climate change
while maintaining the character of historic buildings.
The briefing on the inquiry and the call for
evidence itself acknowledges that the UK's attempt to reduce carbon
emissions will present specific challenges for the management
of the nation's older housing stock and recognises the challenge
of retaining historic interest. English Heritage strongly supports
the principle of improved energy efficiency in buildings, but
we are concerned that poorly considered alterations could do irreparable
harm to England's finite resource of traditional building materials
and structures, and in some cases impair rather than improve their
energy efficiency. Therefore we are keen to ensure that owners,
landlords, specifiers, building control officers and domestic
energy assessors better understand how traditional buildings behave,
and how adaptations might best be chosen to truly improve their
energy performance.
GENERAL POINTS
1. The historic environment is our most
accessible cultural resource and has a powerful influence on peoples'
sense of identity and civic pride. It contributes significantly
to the character and sense of place of rural and urban communities
and lies at the heart of sustainable growth and place-making.
English Heritage is the Government's statutory adviser on all
matters relating to the historic environment in England. We are
a non-departmental public body established under the National
Heritage Act 1983 to help protect England's historic environment
and promote awareness, understanding and enjoyment of it.
2. Britain's stock of traditional housing
account for approximately a quarter of all homes in the UK and
forms part of the character and distinctiveness of our country.
There is therefore a considerable risk from inappropriate or poorly
executed adaptations to improve energy-efficiency. In addition
to the approximately 370,000 listed structures in England, there
are over a million unlisted buildings in England's 9,374 conservation
areas. Our concerns are also relevant to all buildings constructed
using traditional materials and techniques, even those that are
not designated in any way. This means not only the 4.7 million
homes built prior to 1919, before the use of modern impermeable
materials became widespread (English House Condition Survey,
2005), but many later buildings, particularly those constructed
between the wars (according to the English House Condition
Survey, some 3.8 million buildings).
3. To help people understand the impact
of climate change on older buildings, and how they can be adapted
safely and effectively English Heritage is developing a website
for home-owners, Climate Change and Your Home. Real savings can
be derived from benign, relatively low-impact interventions, such
as low-energy light-bulbs, condensing boilers, fitting energy
switches on heating appliances, and improvements in the efficiency
of electrical goods. English Heritage is also preparing extensive
guidance on how best to apply Part L of the Building Regulations
to traditionally constructed buildings.
4. In order to further develop guidance
on best practice in improving traditional buildings we need better
data. Techniques for measuring the energy performance of buildings
are still in development, and must take account of the many different
ways a building can be constructed and the many ways it is used
by the people who live in it. For example with milder winters
likely, is insulation the best approach to long-term planning
for climate change? Insulation could result in homes overheating
in the summer months, perhaps driving up the demand for air conditioning,
and hence increasing rather than decreasing the total energy being
consumed. Stopping heat loss by sealing chimneys and double-glazing
all windows often leads to the occupants throwing open the windows
for fresh air—losing much more heat than the leakage through
the original windows ever did. Asking people to live in a hermetically
sealed home, which maintains a steady internal temperature throughout
the year, is probably unrealistic, and may well prove harmful
to health.
5. In 2008 English Heritage will be embarking
on a long-term study to develop measurement methodologies, and
to use them to monitor a number of Victorian terrace buildings
before and after energy-saving improvements have been made. From
this we and our partners hope to develop robust new approaches
to ensuring that the existing housing stock is as energy efficient
as possible, and we anticipate that the information we gain will
also be of use for designing efficient new homes. It is worth
noting that traditional materials and structures were developed
to be effective in a world where energy was extremely expensive,
and that they may contain positive lessons on efficiency. For
example, solid-wall construction was common, and this is now being
recommended again for eco-friendly housing (Beating the Heat,
keeping UK buildings cool in a warming climate, 2005).
6. The Committee's investigation into existing
housing and climate change, is an important and timely initiative,
and we welcome the opportunity to challenge some of the presumptions
and establish a clearer evidence base for future policy. For example,
Energy Performance Certificates are suggested as a suitable tool
for comparing the energy consumption in different types of dwelling,
but the methodology used by the Reduced Data Standard Assessment
Procedure (RDSAP) calculator was not designed to deal with single
houses, let alone houses built with thick solid walls and permeable
materials. English Heritage has therefore developed guidance for
Domestic Energy Assessors and home-owners, which advises that
any recommendations generated by RDSAP should be applied with
great caution (English Heritage guidance on Home Information Packs,
specifically Understanding SAP Ratings for Historic and Traditional
Homes, which can be downloaded from www.english-heritage.org.uk/homeinformationpacks).
7. In summary English Heritage fully supports
a government-led initiative to look at the impact of the UK domestic
housing sector on energy use, but recommends that it look more
stringently at the underlying issues, for example:
— How can we measure the energy use
of domestic buildings?
— How is energy used in domestic buildings?
How does this vary in different types of building?
— What makes a house energy-efficient?
— How do we take whole-life costs into
account?
— Are there lessons to be learnt from
traditional building techniques and structures?
— How does the way a house is being
used affect its energy efficiency? Are there ways of improving
wasteful usage, without having a detrimental effect on the quality
of people's lives?
— How is energy use in UK homes likely
to alter in response to climate change? For example, will heating
decrease but air conditioning become more common? Will the emphasis
on more insulation today generate an increasing demand for more
cooling?
ENGLISH HERITAGE'S
RESPONSE TO
SPECIFIC QUESTIONS
RAISED IN
THE CALL
FOR EVIDENCE
The significance of existing housing compared
to new build, and the different levels of performance each display
Although there have been some very significant
advances made within the construction sector in improving the
thermal performance of new materials, English Heritage has not
yet seen any compelling evidence to suggest that traditionally
constructed homes perform worse than recently built homes. Historic
building materials are often more durable than their modern replacements
and more cost-effective in energy terms. For example, although
properly maintained softwood window frames have an almost indefinite
lifespan, PVCu windows are usually guaranteed for no more than
10 to 15 years. At current energy prices, this is far less than
the time needed to repay any energy savings.
Policy responses must be based on clear evidence.
It is imperative to collect accurate data on the existing energy
performance of various types of home together with the changes
in performance delivered by appropriate improvement interventions.
To this end we are currently developing a major research project
to look at the overall energy efficiency of traditional homes.
Building on work by others we need to evaluate, for example, how
effective energy saving retrofitting can be accommodated across
a wide range of construction types without compromising either
the character or the long term material integrity of the building.
Recent work by the Ministry of Justice for instance has suggested
that their pre 1900 buildings are the most energy efficient per
square metre and that such buildings should be prioritised for
retention within their property portfolio (Ministry of Justice,
2007 Age Energy Research, A study of the energy usage of buildings
relative to their age). It is essential that everyone with
an interest in this area works closely to identify and share best
practice. We therefore intend to discuss our proposed research
in more detail with Government and construction industry leaders,
to agree parameters for this and similar research, so that together
we can begin to generate meaningful, comparative data.
The existing housing stock may also have a role
in reducing some climate change effects. For example, period homes
in urban areas often have gardens both front and back, and it
is already well appreciated that these play an important role
not just in making our urban areas attractive places to live (see
English Heritage, 2007, Suburbs and the historic environment),
but in enhancing bio-diversity, allowing for exercise, recreation,
and even food production. Now evidence is increasingly showing
that they also play an important role in helping to temper rising
urban temperatures and flash flooding (see for example the ASSCUE
project, Royal Horticultural Society Front Gardens. Are we
parking on our gardens? (2005) and Royal Horticultural Society
Water in the garden. Are we draining our water supplies? How
can gardeners save water? (2007)).
There is a strong public wish to protect such
homes, which offer generous internal and external space (see Greater
London Authority, 2006: Housing Space Standards). Again, traditional
structures may have useful lessons for new buildings.
The respective role of residents, homeowners,
landlords, local government, central government and the energy
industry in promoting and delivering greater energy efficiency
As the government's advisor on the historic
environment, English Heritage has developed a wide knowledge of
how traditionally constructed buildings actually behave, and we
are keen to use this knowledge to assist both government agencies
and the general public.
We are currently preparing extensive advice
on energy efficiency and climate change effects on the traditionally
constructed housing stock and intend to work with the Local Government
Association's Climate Change Commission to promote best practice.
Collaboration with DCMS, CLG and DEFRA should help to identify
ways of communicating these and other important messages through
all our websites, communication material, advice and guidance,
and conferences.
Energy Performance Certificates
We have already released draft guidance on EPCs
and the related HIPs process (copies attached with this submission),
and have also commissioned a qualified Domestic Energy Assessor
(DEA) to survey a range of traditional dwellings using the standard
techniques. Thus far seven buildings have been surveyed, and the
results have confirmed our reservations.
For example, the calculation for a 19th century
two-up two-down terrace house, brick with original sash windows
predicted an annual energy consumption of 448kWh/m2, and suggested
improvements which would bring this down to 307 KWh/m2. Actual
bills (confirmed with the supplier) showed power usage to be 223
KWh/m2: in other words the actual energy use was much less than
that predicted for the house post-improvement. We therefore recommend
that owners supplement the EPC with utility bills which show the
actual energy consumed. We are discussing with CLG the possibility
of a direct link from every EPC to our climate change website
to ensure that easy free access to advice is made as straightforward
as possible for homeowners.
Government efforts to reduce carbon emissions
from existing housing stock whether in private or public ownership
and other related programmes including Decent Homes
English Heritage is concerned that Government
targets to improve the energy efficiency of all dwellings may
lead to inappropriate, damaging and potentially counter-productive
building work to traditionally constructed homes. We would like
to see a more targeted approach to improving domestic energy efficiency
which draws attention to the differences between modern and older
construction materials and methods. Our main concerns are not
simply historic or aesthetic, but equally a desire to ensure that
the performance of traditionally constructed buildings is not
compromised by an imperfect understanding of how they work.
The fundamental difference between modern and
traditional construction is that modern buildings use impervious
materials such as cement and plastic cladding to keep moisture
out, whilst traditional buildings were built using thick permeable
materials such as solid brick and stone masonry, timber and lime
plasters, which can absorb excess moisture and release it slowly
by evaporation. Modern building practice depends on perfect maintenance,
because any leak will let water in but prevent it from escaping.
The so-called "breathable" materials and structures,
by contrast, are affected very little by localised damage, and
are able to buffer large quantities of moisture—(timber
roof beams of a typical house, for example, can absorb large quantities
of water over time with minimal increase in their moisture content),
keeping the internal humidity of an occupied building pleasantly
stable, at no cost to the fabric. This is no accident: traditional
materials and construction techniques were developed by a process
of trial and error lasting several thousand years. Retro-fitting
traditional buildings with modern materials usually dramatically
alters the way the building is working, and all too often results
in damp walls: not just giving a conduit for heat loss from the
building, but also causing serious damage to the fabric.
The technologies available to reduce emissions
and the Government's role in facilitating relevant further technological
development
There are many innovative developments taking
place. Given the extent of the traditional housing stock, we would
welcome more Government support in exploring the potential to
adapt some of these existing technologies to traditional construction.
We are also keen to ensure that traditional materials and methods
are reassessed for use in new build. For example, solid stone
masonry is currently almost unknown (most stonework is cladding),
but it gives excellent thermal protection in both low and high
temperatures. Although the initial costs are significant, stone-masonry
buildings are very long-lived and require very little maintenance,
so the whole-life costs may be very low. English Heritage is to
host a conference at the end of January 2008 that will help explore
some of these issues.
English Heritage is also developing guidance
for home-owners on how investment in micro-renewable energy-generation
technologies can achieve value for money and be implemented without
damaging the appearance, significance or performance of older
buildings. (English Heritage guidance note: Micro Wind Generation
and Traditional Buildings 2007)
Real savings can be derived from benign, relatively
low-impact interventions, such as low-energy light-bulbs, condensing
boilers, fitting energy switches on heating appliances, and improvements
in the efficiency of electrical goods. Using humidistat controls
rather than thermostats on heating can not only reduce the demand
for energy, but minimise the adverse effects on the building fabric
of fluctuating temperatures and humidities.
The costs associated with reducing carbon emissions
from existing housing, who should meet those costs and particularly,
in respect of low-income households, interaction between carbon
emission reductions and the Government's ambitions to reduce poverty.
No comment.
The specific challenges which may arise in relation
to housing of special architectural or historical interest
Traditionally constructed buildings make up
a substantial percentage of homes in the UK, and are likely to
do so for the foreseeable future. According to the recent Housing
Green Paper Homes for the Future: More affordable, more sustainable
(CLG, 2007) the Government has calculated that by 2050 buildings
now in existence will account for two-thirds of homes. Given the
current rate of replacement of UK housing stock—around 1%
per year—we will have to live with our existing buildings
for some time yet. We cannot afford not to take proper care of
our existing housing stock. It is in our interests to ensure that
existing buildings are well managed and maintained, and that any
recommended changes are based on a clear understanding of the
overall effect they will have on the building's longevity as well
as its efficiency.
We all recognise the part that each of us must
play in reducing carbon emissions. Maximising energy efficiency
is a desirable objective for the environment, for the economy,
and for residents. The Code for Sustainable Homes is a
very positive step forward. However, English Heritage is concerned
that a massive programme of standardised improvements may not
be effective and prove to be carbon-costly. We believe that without
a better understanding of how traditionally constructed buildings
currently perform, combined with more reliable ways of measuring
this performance, unnecessary, inappropriate and potentially damaging
improvements will be specified on the assumption of inefficiency.
We are particularly concerned that a drive by Government to improve
traditional homes by adding wall and even roof insulation en masse
could prove counter-productive, not only environmentally but also
financially. As well as the high risk of damp and decay (leading
to costly repair works, and causing the building to lose heat),
the consumption of additional resources, including the carbon
cost of manufacture and transportation of the insulation materials,
must be taken into account. Building waste accounts for 24% of
the total waste in the UK, with the Government's Performance and
Innovation Unit report, Resource Productivity, noting that
"energy is consumed in the production of construction materials
such as bricks, cement and metals and in their distribution...
Over 90% of non-energy minerals extracted in Great Britain are
used to supply the construction industry with materials... yet
each year some 70 million tonnes of construction and demolition
materials and soil end up as waste." (Performance and Innovation
Unit, 2000). How do the costs compare to the benefits to be gained
by insulation? If careful, resourceful consolidation of existing
fabric can achieve good thermal efficiency, to demand extra insulation
on solid walls 40 cm or so thick would be a costly mistake.
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