A total of 742 heat pumps were retrofitted in a variety of UK homes as part of the Electrification of Heat Demonstration Project funded by the Department for Energy Security and Net Zero and led by Energy Systems Catapult.
Four different heat pumps were installed by the delivery contractors – Warmworks (Scotland), E.ON (north east of England), and OVO Energy (south east of England – excluding London). These were; low temperature air source heat pumps (in 41% of the homes), high temperature ASHP (33%), hybrid (20%) and ground source heat pumps (5%).
Average costs of the technology ranged from £9,817 for a hybrid solution, to £24,542 for a ground source pump. Properties included detached, semi-detached, mid-terrace and flats, spanning a variety of ages and energy performance ratings.
The heat pumps were monitored throughout the project to assess their performance, revealing the majority performed well, with efficiencies comparable to three times that of modern gas boilers. While even on the coldest days when temperatures fell to as low as -6o, only a marginal decline in system performance was observed.
When asked for their feedback afterwards, 85% of the participants in the project said they already had, or were likely to, recommend a heat pump to a friend or family member. They highlighted benefits such as their reliability, easy-to-use nature, and low levels of noise.
The project has demonstrated that ‘the large-scale roll-out of heat pumps is possible in the UK’, according to the Energy Systems Catapult, and that they can be installed in various property types.
It coincided with the release of another report – In-Situ Heat Performance – analysing real-world performance data for heat pumps, which revealed both ground source and air source pumps deliver ‘substantial efficiency gains over traditional gas and oil boilers’.
Richard Halsey, Innovation Director at Energy Systems Catapult said: “The findings of the Electrification of Heat Demonstration Project are clear; when designed and installed well, heat pumps can be an effective low carbon heating solution, providing good consumer outcomes regardless of the property type or age. It is time to do away with the idea that they do not work in UK homes, this is simply untrue.”
Overcoming the four main barriers to heat pump adoption
Energy Systems Catapult’s recently published Innovating to Net Zero 2024 report found that the electrification of heat could represent over 70% of total heat supply in 2050. It says that to achieve such a rate of electrification, the four main barriers identified during the demonstration project would need to be overcome.
Perceived impact of disruption
Physical and practical disruption was cited by some participants as being one of the main drawbacks of having a heat pump installed. Heat pump specifiers and installers need to develop innovative solutions to help customers navigate the heat pump installation journey and reduce the impact on householders.
Hard to decarbonise homes
Several property types were identified as posing more of a challenge for the installation of a heat pump. Mid-terrace homes were impacted by space constraints, pre-1919 homes faced challenges owing to building fabric efficiency and heating capacity required, and post-2001 properties needed solutions that worked with microbore pipework. However, the project did install heat pumps across all property types and ages, indicating that such issues were not insurmountable.
Space and noise constraints
A lack of external space and the perceived risk of noise pollution did pose a barrier to the installation of a heat pump. Permitted development rights required heat pumps to be installed one meter away from the property boundary or a neighbouring property to minimise the potential impact of noise on neighbours. This rule does not allow for the actual noise output of the heat pump. This could pose a challenge to installing heat pumps in densely populated areas. The Demonstration Project findings support the ongoing revision of such planning requirements.
Slow grid connection times
There is a need to inform the Distribution Network Operator (DNO) of the intent to connect a heat pump to the electricity network. The time taken to process applications to connect a heat pump can vary and cause significant delays impacting the customer journey and time taken for installation. These delays may mean the difference between installing a heat pump and opting for an alternative heating technology.
Richard added: “The barriers to installing a heat pump are not insurmountable. The project points to a need for a bold reimagining of home heating market design to make it easier for consumers to make the switch to low carbon heating solutions.
“Innovation in heat pump technology has come a long way over the last decade. Heat pumps are more efficient than they’ve ever been, they’re reliable, they work in cold weather and are suitable for most housing types and ages. Where barriers remain, innovation can help tear these down to help make solutions accessible, desirable, and affordable.”
The installation of a heat pump provided an incentive for some participants to make additional ‘green’ upgrades to their homes including installing insulation and other energy efficiency measures such as installing solar panels and battery storage.
Heat Pump Association response
Responding to the findings of the report, Chief Executive of the Heat Pump Association, Charlotte Lee, said: “I am encouraged by the findings of the Electrification of Heat report’s results, which demonstrate improvements in heat pump performance and highlight their potential as an efficient, effective, scalable solution for decarbonising heat in all property types across the UK.
“Furthermore, the report emphasises innovations within the industry, including improvements in refrigerant use such as R290 and R32, which contribute to improved efficiency. Other innovations such as low design temperatures, weather compensation, and mechanical design enhancements are also noted as supporting factors in the ability to accelerate heat pump deployment at scale.”
Many of the homes retrofitted with heat pumps in the project have become part of the Catapult’s network of over 5,000 ‘Living Lab’ homes and will continue to support home energy research and innovation.
A view from industry
Kensa CEO, Tamsin Lishman, said: “This new research shows beyond doubt that heat pumps are the most efficient way of heating homes, three to four times more efficient than gas boilers.
“As a manufacturer and installer of ground source heat pumps, it’s pleasing to see real-world data confirming the technology is the most efficient heating technology available, over 40% more efficient even than air source heat pumps.
“Importantly, the report shows ground source heat pumps perform well even when temperatures drop below zero, meaning reduced electricity demand and less pressure on the grid. This is a critical finding for how we achieve the mass roll-out of heat pumps, with millions of homes poised to switch to electrified heating.
“However, even with these efficiencies, today’s energy prices still mean it’s only slightly cheaper to run a heat pump than a gas boiler in a typical British home. At a time when we need to be weening ourselves off fossil fuels, it doesn’t make sense that electricity is still four times the price of gas. It’s critical the government acts now to remove the levies artificially pushing up the price of electricity.
“Combine the continually improving efficiencies of heat pumps with lower power prices, and we’ll see the significant real-world savings consumers can make by switching to low-carbon heating. With this and ending the installation of gas boilers in new homes, the government can normalise heat pumps in UK homes and kick start the transition to clean affordable heat.”
Image credit: Unsplash