How much does an air source heat pump cost?

Advice to make sure you get the best from your investment.

By Rebecca Foster | 26 March 2021

An air source heat pump cost depends on several factors. But with the possibility of financial support from the Renewable Heat Incentive (RHI), the prospect of switching a gas- or oil-fired boiler for an air-source heat pump (ASHP) seems enticing. Powered by electricity, ASHPs extract warmth from the air, and increase the temperature to supply heating and hot water.

Calculating the cost

The cost of an air source heat pump varies. It depends on the size of the unit, its manufacturer, heat output and its level of performance. The coefficient of performance (COP) is a measure of a unit’s efficiency. The COP shows how much usable energy is extracted from the air compared to how much electricity is used to power the pump. A COP of four means that for every 1kW of electrical energy used, 4kW of heat is generated. The higher the ratio, the more efficient the unit and the more efficient its heat delivery. To compare like with like, look for the seasonally adjusted indicator of performance (SCOP). This shows how effective heat pumps are on an annual basis. It indicates the ratio of the heat output to the supply of total electrical energy over the year.

Some models provide both heating and cooling. These models tend to be more expensive. ‘The average cost of an air source heat pump for a three-bedroom detached house is between £8,000 and £10,000,’ says Max Halliwell, heat pump specialist at Mitsubishi Electric. An installation that meets qualifying criteria is able to benefit from financial incentives provided by the the Renewable Heat Incentive (RHI).

Barn conversion designed by Pad Studio.

Barn conversion, Pad Studio, with Mitsubishi Ecodan ASHP. Photo: Nigel Rigden

Running cost comparision

Estimates from quote-comparison website Greenmatch show that for an average four-bedroom house with an ASHP, annual heating costs start at £759. ‘Compared to a gas boiler, an air-source heat pump requires a lot less input energy. But gas can be cheaper than electricity,’ says John Taylor, managing director of Enhabit. Improve your home’s thermal envelope by ensuring the building is airtight and well-insulated. This reduces demand on the heat pump and keep the running costs in check.