• 85% of Electrification of Heat Demonstration Project participants either had, or were likely to, recommend a heat pump to a friend or family member
• 742 heat pumps were installed in a variety of UK homes and demonstrated their effectiveness as a heat source regardless of property type or age
• Challenges to a large-scale rollout of heat pumps are not insurmountable but require targeted innovation in consumer engagement and the delivery of heating experiences that meet the wants and needs of consumers   

85% of participants in the Electrification of Heat Demonstration Project had already or, were likely to recommend a heat pump to a friend or family member, citing their reliability, easy-to-use nature, and low levels of noise.

Funded by the Department for Energy Security and Net Zero (DESNZ) and led by Energy Systems Catapult with support from LCP Delta and Oxford Computer Consultants, the Electrification of Heat Demonstration Project sought to understand the technical and practical feasibility, and constraints of a mass rollout of heat pumps into British homes.

A total of 742 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) – into a broad spectrum of housing types (41% detached, 43% semi-detached, 11% mid-terrace, and 6% flats) and ages (68% pre-1980).

Heat pumps were installed in homes with varying Energy Performance Certificate (EPC) ratings from A down to G. At least 53% of homes involved in the demonstration project had an energy efficiency rating of C or D before the heat pump installation.

Four different heat pump types were installed, Low Temperature Air Source (LT ASHP) 41%, High Temperature Air Source (HT ASHP) 33%, Ground Source (GSHP) 5%, and Hybrid 20%. These heat pumps were monitored throughout the trial to assess their performance. The majority of heat pumps 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 -6^o, only a marginal decline in system performance was observed.

The project has demonstrated that the large-scale rollout of heat pumps is possible within the UK. It has shown that heat pumps can be successfully installed in all the types of property which were tested by the Project. It has also shown that they can operate with good efficiencies and provide positive consumer heating experiences.

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.”

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. To achieve such a rate of electrification, the barriers identified by the Demonstration Project will need to be overcome. Four common blockers and barriers to the mass rollout of heat pumps were identified by the Project:

Perceived impact of disruption

Compared to the installation of a traditional gas boiler, the heat pump installation journey may be more complex for consumers. 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 continued: “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. Barriers such as the ‘one metre rule’ are not based on tangible noise outputs and so do little else but discourage some homeowners from making the switch to a heat pump. If we’re to transition away from natural gas boilers we need to be doing more to remove the barriers to uptake.

“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.