Expert advice to make sure you get the best from your green energy investment
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 Renewable Heat Incentive (which closes to new applications at midnight on 31 March 2022).
Running cost comparison
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.
The Boiler Upgrade Scheme
You might think an air-source heat pump pricey at £8,000-£10,000, but a ground-source heat pump is even more expensive, starting from around £13,000 (plus, you need a lot of land for this option). In a bid to reduce this expense, the government’s new Boiler Upgrade Scheme (announced on 18 October 2021) will make £5,000 grants available to reduce the cost of low-carbon heating. Running over a three-year period from April 2022, the initiative has £450 million in funding.
Manufacturers and the government are consulting on solutions to drive down the price of heat pumps and make them on a par with fossil fuel boilers by 2030. Providing ministers succeed in reducing the price of electricity over the next decade, by shifting levies away from electricity bills, the running costs should be no higher either.
The government has pledged to achieve 600,000 installations every year by 2028, but there’s a long way to go. Industry figures show that, in 2019, only 35,000 heat pumps were sold in the UK, compared to 1.67 million gas boilers.