Understanding how to increase the appeal and performance of heat pumps draws on the findings from an Energy Systems Catapult trial conducted over the winter of 2018-19 to understand if homeowners could use a hybrid heating system to get comfortably warm at home.

The Catapult integrated a smart control system with an Air Source Heat Pump and the homeowners’ existing gas boiler to create a low carbon hybrid heating system. We then recruited five members of the public who were willing to trial the system and installed it in their homes.

The research goals of the trial were to:

• Identify if trialists could control the system to deliver their required heating outcome
• Explore how the performance of the hybrid heating system compared with a gas boiler
• Understand how results in real homes compare with Salford test-house in terms of ability to achieve required comfort levels
• Explore insights into requirements for more sophisticated control solutions for hybrid heating systems to perform as well as or better than gas boilers
• Explore insights into the potential for hybrid heating systems to support future heat as a service value propositions.

This report was published alongside two related reports, ‘Using the Living Lab to sell consumer centric heat services that encourage adoption of low carbon heating’ and ‘Insight Paper: Lessons from running the Living Lab’.

All three projects were funded by the Department of Business Energy and Industrial Strategy.

Key points

• It was hard to find homeowners with gas boilers who wanted a heat pump, even though it was being offered for free. They worried about energy bills, maintenance costs and, due to a lack of familiarity with the technology, what ownership of a heat pump entailed.
• All participants were able to use their hybrid heating systems to reach the temperatures they wanted. They reported levels of comfort that were as good as, or better than they had reported with their gas boilers, though the improvement was not significant.
• All participants were reluctant to make expensive investments to improve the energy efficiency of their homes just to enhance the performance of their heat pump. They were more interested in less costly upgrades and tangible benefits, such as lower bills or greater comfort.
• To decarbonise domestic heat much higher numbers of consumers will need to replace their gas boilers with low carbon alternatives. Four participants were open to removing their gas boilers and relying only on a heat pump to warm their home if they could buy their heat as a service. This might bundle the costs of their heating system, installation, servicing and heat into one fixed weekly cost.
• They also said they would be more confident heating their home for longer periods to suit a heat pump if they could have cost certainty through a fixed price. Including the costs of any maintenance might also reduce their concern about installing unfamiliar heating technologies.