Environmental Change Institute

Exploring the time dimension of low carbon retrofit: owner-occupied housingTina Fawcett Building Research & Information, 2013 p1 -12 http://dx.doi.org/10.1080/09613218.2013.804769

Context & research questionsLow carbon retrofit* occurs on a very small scale in the UK – probably only in hundreds of properties per year, compared with the hundreds of thousands needed annually to meet our national carbon reduction goals.

Low carbon retrofit is most commonly understood as a one-off activity. However, an alternative model is of retrofit occurring ‘over time’- a more gradual process which still delivers significant carbon savings.

Does this occur in real life?** And if so:

•Could over-time low carbon retrofit be an attractive option for owner-occupiers?•Could over-time low carbon retrofit deliver sufficient carbon and energy savings?•What would be needed to support over-time low carbon retrofit?

*Here defined as reducing carbon emissions by at least 60%** SPOILER ALERT: yes it does

My research questions

‘Over time’ low carbon retrofit does exist

The Superhomes database had timing information about 35 owner-occupied low carbon retrofits. Of these, 17 were retrofitted as a one-off package of work and 18 retrofitted over time.

Several householders described their low carbon retrofit experience as a journey or a continual process:

“Our journey has definitely been step by step, and we keep going.(Superhomes owner, Coventry)

Where it’s been sensible and affordable over the years we’ve done things to make the house more energy efficient and comfortable.(Superhomes owner, Wendover)

It hasn’t really been a project, but a process ofsteady improvement.(Superhomes owner, Steeple Claydon)

Could over-time low carbon retrofit be an attractive option for owner-occupiers?

Buildings, people and time: Over-time retrofit fits with existing patterns of regular spending on home maintenance, repair and improvement. An over-time low carbon retrofit, involving a series of distinct stages, fits better with most people’s previous experience of commissioning and managing smaller scale building works than a one-off whole house low carbon retrofit. It can be added on to existing ‘conventional’ building works.

Cost: We don’t yet know whether one-off or over-time retrofit would be more expensive.

Disruption: Disruption patterns are very different for one-off and over-time works – and personal preferences may differ.

Answer: Yes, for some.

Could over-time low carbon retrofit deliver sufficient carbon and energy savings? (1)

time

Carbon

emissions

One-off retrofit

or

Over-time retrofit

Could over-time low carbon retrofit deliver sufficient carbon and energy savings? (2)Modelling work (EST 2011) suggests in theory that step-wise retrofit can lead to high levels of carbon saving.

Analysis of the potential for ‘locking out’ savings (by retrofitting to a sub-optimal level) shows it may be no greater for over-time than for one-off retrofits.

However, to meet very ambitious retrofit standards such as ENERPHIT, which require extensive changes to the building fabric, an over-time approach is not likely to be appropriate.

So – there are signs it could deliver high (but perhaps not the very highest) levels of savings, but not a great deal of empirical evidence as yet.

What would be needed to support over-time low carbon retrofit?

Creating new policyNew policies to support over-time retrofit could include: •a suitable metric•additional training for building professions and trades•development of Low Carbon Retrofit Plans

Amending existing policy•Measures to reduce cost to householders (e.g. subsidies, subsidised loans) to apply also to over-time retrofit. •Innovation on technologies and management of over-time retrofit.•Training to help professionals to spot low carbon retrofit opportunities when doing other work, working in a way that is compatible with future upgrades to the property, and understanding Low Carbon Retrofit Plans.•Creating obligations to act – e.g. a programme of increasing minimum standards over time

ConclusionsOver-time low carbon retrofit has been shown to exist in the real world and to deliver significant carbon savings. However, the empirical evidence base is small.

An over-time model implicitly assumes that home owners and professionals will be in a process of continual change, adapting themselves, their skills and their homes to a low carbon future.

The over-time approach is likely to increase the accessibility of low carbon retrofit by spreading costs and aligning low carbon retrofit with normal repairs/ upgrades. It offers a vision and mechanism of migrating from a current situation of very little low carbon retrofit to a much improved housing stock and more engaged population.

While many detailed research questions remain, preliminary analysis has shown that over-time retrofit is worthy of further exploration.

Acknowledgements & further research

The research reported in this paper was jointly funded by the Engineering and Physical Sciences Research Council (EPSRC) and EDF through the People, Energy and Buildings programme (EP/H051163/1). Any views expressed in this paper are those of the author alone and do not necessarily represent theviews of the funders.

Since completing this paper, colleagues and I have continued to work and gather evidence on this topic. Look out for further papers by Fawcett, T and Killip, G in the coming months.

November 2013