Some of the earliest examples of purpose-built social housing in the UK can still be found tucked away along central London’s more affluent streets. Built in Edwardian baroque style, the Sutton Dwellings in Chelsea are perhaps an unlikely site for an innovative scheme at the new frontier of Britain’s low-carbon journey. This winter more than 80 of the estate’s flats will be warmed by heat pumps that tap the warmth of the earth well below the streets of central London. The scheme’s 27 boreholes burrow deep into the ground directly beneath the estate to where piped water is warmed and fed to a network of “shoebox” heat pumps in a cupboard in each flat. Here, each heat pump – roughly the size of a gas boiler – tops up the heat of the water pipes so that each household can control their own heating, setting it to their preference or using thermostats. The scheme was completed in late autumn as part of a refurbishment of the more than 100-year-old block of flats, confounding the myths around the UK’s heat pump roll out, such as claims that they do not work in older buildings. It aims to show that heat pumps are not only for newer buildings and that ground source heat pumps are not only for homes with extensive outdoor space. The developer, Kensa, has completed schemes across the south-east of England, installing shoebox heat pumps in 273 flats across multiple 1960s tower blocks in Thurrock, Essex, and in more than 400 flats across eight tower blocks owned by Enfield council. The Sutton Dwellings project proves that prewar housing can benefit, too. “Often you see claims heat pumps don’t work, they aren’t suitable for older buildings, there isn’t enough space to install ground source heat pumps in cities,” said Stuart Gadsden, a commercial director at Kensa. “Hopefully, this project can serve as a blueprint for other social housing providers with properties that need decarbonising.” Heating the UK’s 28m homes accounts for almost a fifth of the UK’s greenhouse gas emissions, and as temperatures drop this winter, ministers will face rising questions over its plan to tackle this area of the economy. The government is expected to set out the full details of a major funding plan in the coming weeks. Air source heat pumps are expected to play a big role; according to some forecasts, the outdoor heating units will replace gas boilers in more than 40% of homes. A fifth of homes could have a ground source heat pump for heating and hot water. Kensa believes its network approach may help to upgrade social housing and tower blocks across the country, and could even be adapted to meet the heating needs of entire streets, with boreholes prepared in advance for homes to connect to when they choose to upgrade their heating system. Making low-carbon heating an affordable – and desirable – alternative to traditional gas boilers will be key to the success of the government’s ambition to create a net zero economy by 2050. Less than two miles from Sutton Dwellings at the Lillington Gardens estate in Pimlico, residents are deeply sceptical. Here, leaseholders have been warned by Westminster city council that they could face bills of between £30,000 and £66,000 each to replace its buckling heat network. The council has proposed a low-carbon scheme that would cost up to £185m and help the local authority reach its target of becoming net zero by 2030. In the 1960s, the Lillington heat network was once at the vanguard of low-carbon home heating, making use of the waste heat emitted by miles of underground pipes from the nearby Battersea power station. Since then the network has come to rely on centrally located gas boilers and has fallen into disrepair, leaving residents to battle burst pipes, hot water leaks and sewage spills. The Labour-led council has blamed “historic underinvestment” for the failure of the heat network and said it is costing £3.5m a year in insurance to manage the “constant leaks that have negatively affected the lives of residents”. The councillor Liza Begum said the council was working with residents to urgently find a long-term solution, and reduce the costs for residents and leaseholders. The council has joined the Greater London Authority and London councils in a pan-London consortium bid for government funding that aims to help provide low-carbon heating projects and heating upgrades to low-income homes in England. Huge funding opportunities have been promised by the Labour government but the details of how such schemes will work are not known. The Treasury used its first budget since Labour came to power to promise £3.4bn for the warm homes plan; it is considered the first phase of an ambitious £13.2bn commitment over this parliament to increase the grants available to homes that choose to swap their gas boilers for heat pumps and to upgrade the energy efficiency of Britain’s draughtiest housing stock. Households connected to communal or district heat networks are often paying twice as much for their heat as those with their own gas boiler, according to Heat Trust. The consumer champion for heat network users has urged the government to help lower their costs by bringing in two reforms: first to extend the energy price cap to include homes connected to a heat network, and second, to provide support to help cover the costs of repairing old heat networks. Stephen Knight, the chief executive of the Heat Trust, said: “Heat networks will have an increasing role to play in how we heat our homes in cities and towns in the coming decades, as we move away from a reliance on gas boilers. However, we currently see too many examples of poorly designed, inefficient heat networks that generate heat using expensive commercial energy contracts. This often results in high heating bills for their residents as the end consumers.”