Heat pump stats alleviate cold weather performance fears

Concerns that heat pumps do not perform well in cold weather have been “put to bed”, according to Marc Brown, business leader for homes at Energy Systems Catapult.

Brown’s comments come following the publication of interim heat pump performance data released by the government-backed Catapult as part of the Electrification of Heat Demonstration Project.

An analysis of the data by the Catapult concludes that heat pumps are three times more efficient than gas boilers.

It adds that “Air Source Heat Pumps (ASHPs) can operate with high efficiencies, even in cold weather conditions”.

Part of the demonstration project’s brief was to analyse the performance of heat pumps on some of the country’s coldest days (where mean daily temperatures fell to as low as -6oC).

Analysis of the data “found only a marginal decline in whole system performance”.

It adds: “The median ASHP system efficiency was 2.44 (or 244%) on the coldest days of the year. This result indicates that heat pumps continue to operate with high efficiency – providing the requisite heat to homes – in a wide range of property types even in cold weather conditions.”

As part of the demonstration project, a total of 742 heat pumps were installed by the delivery contractors – Warmworks, E.ON, and OVO Energy – into a broad spectrum of housing types and ages. These heat pumps are being monitored throughout the trial to assess their performance.

The interim data covers this monitoring conducted between November 2020 and August 2022.

The report also concludes that high temperature ASHPs had comparable efficiencies to low temperature ASHPs, indicating that they are a viable solution to reduce home retrofit requirements.

Brown added: “The interim findings of the Electrification of Heat Demonstration Project highlight just how far the industry has come in innovating to improve the performance and efficiency of heat pumps.

“With the release of this data, we can finally put to bed the notion that heat pumps do not work in cold weather conditions and that they are inefficient to run. We’ve observed the exact opposite. They are three times more efficient than gas boilers and work in cold weather conditions. Innovation is changing the game in the heating sector.”

He added: “While we’re taking steps in the right direction, we should not grow complacent. At the risk of sounding like a broken record, innovation and training are critical to the success of a mass rollout of heat pumps.

“We’ve done the hard work and demonstrated that heat pumps work – the UK is heat pump ready. Now we need to apply those learnings. Government and industry should commit to investing in upskilling existing installers in low carbon heating solutions and doing more to attract new talent into the sector.

“This should be coupled with public and private investment in innovation to help transform the sector and deliver on our Net Zero ambitions, without losing sight of the consumer. Get this right and we can be a world leader in green heating solutions.”

The government unveiled ambitious targets in 2020 to install 600,000 heat pumps per year by 2028 – up from 30,000 annually at that point.

Last month, the Sustainable Energy Association warned that focussing on a set target of heat pumps could in fact prove counterproductive to efforts to decarbonise the UK’s heating network.

Despite the SEA’s concerns a senior civil servant within the Department of Energy Security and Net Zero said the government would be sticking with its targeted rollout.

Last year, the National Infrastructure Commission raised doubts over the plausibility of the government’s heat pump target.