100-year-old London flats seek to bust a big heat pump myth

A 100-year-old estate in London has become the oldest block of social housing in the UK to be fitted with a heat pump network.

The pre-first World War Sutton Dwellings estate in Chelsea is solid proof that heat pumps do work well in older buildings, contrary to some claims, according to the supplier Kensa.

Heat pumps are one solution to the world’s fossil fuel emissions – providing renewable heating and hot water in place of gas boilers. But there is still significant public confusion about how the tech works exactly, and a number of myths circulating about their limitations.

“Hopefully, this project can serve as a blueprint for other social housing providers with properties that need decarbonising,” says Stuart Gadsden, commercial director at Cornwall-based Kensa.

A total of 81 flats across four blocks in Sutton Dwellings have been fitted with a ground source heat pump system, which sources heat from the ground beneath the estate. 

“While this can be seen as a great myth-busting project for renewable heating, particularly ground source heat pumps, the most important outcome will be the benefits felt by residents,” Gadsden adds. 

“With our systems they will be getting low cost, low carbon heating and hot water, allowing them to keep their whole homes warm.”

How do the heat pumps fit into older flats?

Built in 1913, the Edwardian-era estate stands as a grand example that heat pumps can be retrofitted to older buildings without compromising their heritage.

Like traditional gas boilers, the heat pumps are small enough to be housed inside a cupboard in each flat. Unlike fossil gas, renewable heat energy is sourced from the ground via 27 boreholes drilled deep below the building.

Ground source heat pumps were the obvious choice in this case. While air source heat pumps are generally composed of an outdoor and indoor unit, networked heat pumps don’t impinge on the red-brick exterior, or take up precious outdoor garden space. 

This is the urban estate’s ‘third era’ of heating after transitioning from coal fireplaces to gas and now low-carbon heat pumps.

How much are the ground-source heat pumps costing residents?

The London project also challenges the criticism that heat pumps are necessarily expensive.

For these social housing residents, annual heating costs will be close to £300 (€360) for a 1-bed flat and around £700 (€840)  for a 4-bed flat, according to Kensa. 

It follows other major social housing retrofit projects completed by the company – including the installation of shoebox heat pumps in 273 flats across multiple 1960s tower blocks in Thurrock, Essex, and more than 400 flats across eight tower blocks owned by Enfield Council.

With 80 per cent of UK buildings expected to still be standing in 2050, Kensa says networked heat pumps are a way to decarbonise the country’s old housing stock. And – crucially – help meet the government’s aim to transition to a net zero economy by mid-century.