Newbuild homes get all the attention when it comes to cutting-edge eco-design. But the UK's 26m existing homes pump out 26% of its carbon emissions, according to latest government figures. And given that 85% of those homes will still be around in 2050 - when the government wants carbon emissions slashed by 80% - established housing stock forms a vital part of the equation.
Last month the Homes and Communities Agency announced seven housing projects across England - mostly involving new homes - that would share in £8.8m under the second round of its low carbon infrastructure funding to allow more homes to access low carbon energy plants. Initial funding of £12m was allocated to similar schemes in July. Two of the projects to benefit in the latest funding round involve retrofitting existing housing, which experts welcome as a step in the right direction towards helping older homes become low carbon.
"You can't tackle climate change without tackling our homes; the numbers are just so great," says Colin Butfield, chair of the Existing Homes Alliance and head of campaigns at the WWF (formerly World Wide Fund for Nature). "We have extremely inefficient housing stock in the UK so we have a long way to go, especially when you look at the government's demanding carbon targets for 2050."
Once you add the cost of retrofit to these challenges, it is no wonder many housing associations feel hamstrung. Olivia Powis, a regional manager and retrofit expert at the National Housing Federation (NHF), says associations cannot claw back retrofitting costs. The NHF estimates retrofitting existing properties - adding solar panels or better insulation, for example - can be £20,000-£25,000 per property. "We would like to be able to recoup the cost from the tenant either from the rent or service charge, and that cost would be offset to the tenant by lower fuel bills, so there would be no extra charge to the tenant overall," she says. She suggests the use of the government's Carbon Emissions Reduction Target (Cert) funding.
Drum Housing Association in Hampshire has won numerous awards for its refurbishment schemes, exceeding government targets on CO2 reductions. In its current 20-home £570,000 retrofit project, the majority of units achieve a 70% reduction, and those with solar thermal and photovoltaic panels reach 79%. But sustainability and innovation manager Paul Ciniglio says the targets are confusing because they include emissions from residents' appliances: "An 80% reduction is really a big challenge and people don't realise." He believes housing associations have been too piecemeal in their approach to retrofitting. It is crucial, he says, to conduct carbon modelling [a form of analysing carbon emissions] both before and after refurbishments to monitor exactly how effective and close to the targets work has been.
There is much that can still be done, however. The Homes and Communities Agency (HCA) advises using modern high-efficiency boilers rather than old-style non-condensing boilers. Butfield recommends basic measures such as coating the outside of tower blocks with an insulated render to cut heat loss by 15%. "Make the shell of the build, insulating walls, roofs and floors ... as airtight as possible." But more guidance is needed. "What would benefit housing associations most would be a very clear government policy on how to retrofit the 26m homes in the UK," he says
• Energy Saving Trust: energysavingtrust.org.uk/home-improvements