The challenge to achieve zero carbon in urban Conservation areas in the UK

1. EcoVert Solutions
Energy efficient solutions for heritage housing
The challenge in
achieving zero carbon
in Urban Conservation Areas
Tim Hulse
GreenBuild EXPO 2012
9th May 2012

2. EcoVert Solutions
Energy efficient solutions for heritage housing
Objective: to significantly lower
the energy in use
of traditional buildings using
sustainable materials

3. Background
• 9.3m hard to treat homes, 7.9m solid-
walled
• 1.2m homes in10,000+ CAs
- 575k Listed or in CAs in Greater
London alone
• 600k retrofits/year - 7/working minute
implies 27k homes in CA’s/year, or one
every 3 minutes

4. What is a Conservation
Area?
• ‘any areas of special architectural or historic
interest, the character or appearance of
which it is desirable to preserve or enhance’
• Main focus is on external appearance -
materials and details are extremely
important
• According to Clair Craig, EH, historic
environment is already a part of sustainability

5. Density of homes in
CAs
Source: Bottrill, 2005

6. What does an urban
CA look like?

7. Energy performance of
buildings in CAs
• No specific data for CAs but 3m
homes have an SAP rating of 30 or
less
(Bands G & F)
• Most are likely to be
solid-walled...

8. Ways to save energy
are well understood

9. Restrictions
• Apart from the intrinsic limitations of certain
properties (e.g. small room size conflicts
with IWI, back yard precludes GSHP)...
• Certain buildings are ‘exempt’ from the
energy efficiency requirements of Part L - ‘to
the extent that compliance would
unacceptably alter their appearance or
character’
• Article 4 directions remove permitted
development rights

10. But bigger issue than
just CA’s
• If building is also Listed, then
Consent is required for both
internal or external alterations
which will affect its character
• If building of ‘Traditional
Construction’ then ‘special
considerations’ also apply

11. Tension between conservation
and sustainability
• Very few management plans
yet exists for CAs
• In those available little about
how to make them more
sustainable or relationship
between sustainability and
conservation
• Current focus appears to be
on not changing anything or
re-instating ‘traditional’
features

12. How can CAs meet
2050 requirements?
• In practice...
• Changes to the front and side
elevations will be difficult
• Almost certainly restrictions on
where solar is allowed - e.g. North
facing roof only!

13. Yet much can be done...
• 60%+ - Old Homes Superhomes
• 79% - Culford Road
• EnerPHit - Grove Cottage
• 81% - Corkland Road
• National Trust
• English Heritage

14. Yet much can be done...
• Retrofitting Soho
Top 10 measures:
9 water saving Retrofitting Soho 2012
8 electric to gas htg, combi boilers
7 secondary glazing, push fit
6 loft insul
5 mech heat extract and recovery
4 draft proofing
3 CHP - from domestic scale up
2 LED lighting © All images this slide - Sturgis Carbon Profiling, Westminster City Council, English Heritage, Soho Community Environment Fund, Gifford and Donald Insall Associates
1 install energy display meters
Key findings: 55% reduction in carbon footprint possible with above
measures, average saving of £650/yr/flat, improved social and
environmental value.

15. But issues...
• How old buildings perform in practice is
poorly understood
- Only recently understood for example
that Sash windows could be made
(relatively) energy efficient

16. Issues...
- Work ongoing to understand how
buildings actually work (e.g. SPAB, Dr.
Caroline Rye)

17. Issues...
• Old buildings often more complex
and built in stages
- Most houses different
- Detailing often complicated
- Thermal bridging a major issue -
one exemplar included 37
junctions across 32 junction types
- Issues with application of SAP
according to EH

18. Issues...
• Breathability - important or
not?
- EST - and Superhomes -
are ambivalent in advice
for instance
- Kingspan is not
- Nor is NBT!

19. Issues...
• Work by Joseph Little has
challenged how much
insulation you can safely
install inside a solid-wall
- Yet disconnect in advice
given e.g. Glaser versus
Wufi (Glaser still used
by EST, DECC, GD for
example)

20. Issues...
• Refurb is expensive
- £46k required to achieve 80%
reduction (NRC, 2012)

21. Thinking outside the
box?
• If all solid-walled buildings were
insulated using hempcrete in ‘most
likely’ scenario, sequestration could
‘generate’ energy for 4.5% of UK
homes
Wright et al, 2012

22. Conclusion
• When we understand what we’re dealing with
better, the solutions may be clearer
• Need for standardisation to reduce cost is
imperative but difficult to achieve
• Need clear guidance/industry acceptance on
e.g.
• Is breathability important?
• How much IWI is ‘safe’?

23. Nevertheless...
• Improving from Band G to B is relatively
straightforward
• While some constraints exist in CAs, relatively
speaking, their impacts can be worked around with
some creativity
- Although harder - or impossible - if the property
is listed
- Need to consider using materials with lower
embodied energy and which can sequester carbon

24. Final thought
“Change will not be easy. It is the
very historic environment, the
narrow streets, the architecture, the
mixture of uses, the ambience of
these central core areas that people
love to visit and work in. We can’t
knock great swathes of buildings
down and start again with ‘eco
architecture’. Soho is a conservation
area with a high concentration of
listed buildings. We have to retrofit
what we have.”
Matthew Bennett, Soho Community
and Environment Fund

25. Thank you
www.ecovertsolutions.co.uk
Energy Efficient Solutions for Heritage Housing
@ecovertsol