The challenge in achieving zero carbon

in Urban Conservation AreasTim Hulse

GreenBuild EXPO 20129th May 2012

EcoVert SolutionsEnergy efficient solutions for heritage housing

Objective: to significantly lower the energy in use

of traditional buildings using sustainable materials

EcoVert SolutionsEnergy efficient solutions for heritage housing

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

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

Density of homes in CAs

Source: Bottrill, 2005

What does an urban CA look like?

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...

Ways to save energy are well understood

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

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

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

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!

Yet much can be done...

• 60%+ - Old Homes Superhomes

• 79% - Culford Road

• EnerPHit - Grove Cottage

• 81% - Corkland Road

• National Trust

• English Heritage

Yet much can be done...• Retrofitting Soho

Top 10 measures:9 water saving8 electric to gas htg, combi boilers7 secondary glazing, push fit6 loft insul5 mech heat extract and recovery4 draft proofing3 CHP - from domestic scale up2 LED lighting1 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.

Retrofitting Soho 2012

© All images this slide - Sturgis Carbon Profiling, Westminster City Council, English Heritage, Soho Community Environment Fund, Gifford and Donald Insall Associates

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

Issues...

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

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

Issues...

• Breathability - important or not?

- EST - and Superhomes - are ambivalent in advice for instance

- Kingspan is not

- Nor is NBT!

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)

Issues...

• Refurb is expensive

- £46k required to achieve 80% reduction (NRC, 2012)

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

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’?

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

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

Thank you

@ecovertsol

www.ecovertsolutions.co.ukEnergy Efficient Solutions for Heritage Housing