Hundreds of millions of pounds must be spent to achieve 80% cuts in greenhouse gas emissions by 2050, report shows

Hundreds of millions of pounds must be spent on the UK’s draughty housing stock to meet the government’s climate change targets, with progress so far too slow to make the difference needed.

Repairing existing homes to a high standard, with insulation and renewable energy technology, would cut consumer bills and bring health improvements, a new report shows.

Domestic housing accounts for about a fifth of the UK’s greenhouse gas emissions, mostly from heating and hot water. But attempts to bring these down have largely failed, prompting renewed calls from experts for a national programme of home improvement that would make dwellings low-carbon for the next 30 years.

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New research by the Institution of Engineering and Technology and Nottingham Trent University has found that meeting government targets of 80% cuts in greenhouse gas emissions by mid-century would require sweeping policy change.

“A national programme for a one-off deep retrofit [of all residential property] is needed,” said Marjan Sarshar, professor of sustainability and the built environment at Nottingham Trent University. “Costs will come down as we build up the supply chain capacity.”

The report’s authors suggest starting with social housing, which makes up about 4.5m homes. By engaging a whole locality at a time, the costs can be brought down and retrofit schemes carried out more efficiently.

It can cost about £17,000 to retrofit a standard house. The benefits go beyond emissions savings, also including lower energy bills, warmer homes and a much-decreased burden on the NHS, which currently spends about £1.4bn a year treating conditions that arise from poor housing.

Costs for ongoing maintenance, amounting to £5.2bn a year for social housing alone, would also be drastically cut or eliminated by a one-off “deep retrofit” for most residential buildings. Social housing tenants spend £4.2bn a year on energy, a big chunk of most household budgets, which would also be much reduced if their homes were insulated and fitted with renewables such as solar panels.

Insulation for roofs and walls, new windows and doors, small-scale renewable energy such as solar panels or district heating systems, are the basic techniques. But instead of deploying them piecemeal, as in the past, the government should start a system of “deep retrofits”, by which each dwelling would receive a one-off refurbishment covering all the needed improvements and make the homes fit for the next 30 years at least, the report found.

The technology, materials and skills needed for these deep retrofits are all available and well understood, but the UK’s failure to put them into practice has prevented the development of a large industry carrying out such work. Successive government attempts to solve the problem have run into problems and been abandoned. The Green Deal, for instance, which supplied loans and grants to people to have insulation installed, was scrapped after only a few years and has not been replaced.

Public perception of the value of insulation took a blow when the Grenfell fire, in which 72 people died, exposed the risks from flammable cladding on tower blocks. However, high-quality cladding and other retrofit technologies should be a priority, and a public information campaign to engage householders could allay people’s concerns, the experts said.

“We need to reassure people that there are safe solutions,” said Richard Miller, director of Miller-Klein Associates and a lead author of the report. “There is a job to be done.”

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Retrofitting a typical house can take several weeks, but the residents can remain living there throughout. Many people are reluctant to take on the inconvenience and cost of such building work but the government could offer incentives and subsidies, which along with the savings on energy bills could make the proposition more attractive.

The report’s authors also called for cities to get involved by setting up programmes to retrofit properties street by street.

The barriers to retrofitting at present were found to be a lack of customer demand, because the energy savings were not enough to tempt people to do the work; lack of government policy; high costs because of the lack of demand; and the difficulty for households of gaining the initial finance needed to embark on the work.

Houses built now, even if they are constructed to a high standard, will make up only a fifth of the housing stock by 2050, the experts found, so retrofitting existing buildings must be the priority.