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Generating renewable energy

Air source heat pumps


  • could lower your fuel bills
  • will cut your carbon emissions
  • can heat your home and hot water

Air source heat pumps (ASHPs) absorb heat from the outside air to heat your home and hot water. They can still extract heat when air temperatures are as low as -15°C.

Air source heat pumps need electricity to run, but because they are extracting renewable heat from the environment, the heat output is greater than the electricity input. This makes them an energy efficient method of heating your home.

If you have large garden space outside, you could consider a ground source heat pump. Despite the greater upfront cost of installing a ground source heat pump, this type of pump is more efficient when it comes to heating your home, which results in higher fuel savings and lower energy bills.

How do air source heat pumps work?

Heat from the air is absorbed at low temperature into a fluid. This fluid passes through a compressor, increasing the temperature, and transfers that higher temperature heat to the heating and hot water circuits of the house.

Watch the video below to find out more.

There are two main types of ASHP: air-to-water and air-to-air. Choosing an air-to-water or an air-to-air system will determine the type of heat distribution system you need.

Benefits of air source heat pumps

It could lower your fuel bills, especially if you replace conventional electric heating. 

It could provide you with an income through the UK Government’s Renewable Heat Incentive (only applies to air-to-water heat pumps).

It could lower home carbon emissions.

There are no fuel deliveries needed.

It can heat your home as well as your water.

Unlike gas and oil boilers, heat pumps deliver heat at lower temperatures over much longer periods. If you are installing an ASHP to replace a gas or oil boiler, you should consider whether you can also upgrade your insulation to get the most out of your ASHP. You might also consider fitting larger radiators or underfloor heating.

Is an air source heat pump suitable for me?

If you’re thinking of installing an air source heat pump, you can view case studies and examples of homeowners who live in Scotland who have installed an air source heat pump.

We also have case studies of Energy Saving Trust colleagues who have made the switch to the low carbon heating technology, which you can read below.

To tell if an air source heat pump is right for you, there are a few key questions to consider:

Costs, savings and financial support


Installing a typical system costs around £7,000 – £13,000. Running costs will vary depending on a number of factors including the size of your home, how well insulated it is, and what room temperatures you are aiming to achieve.


How much you can save will depend on what system you use now, as well as what you are replacing it with. Your savings will be affected by:

Potential annual savings of installing a standard air source heat pump in an average sized, four-bedroom detached home:

England, Scotland and Wales

Northern Ireland

Financial support

You may be eligible to receive payments for the heat you generate using a heat pump through the UK Government’s Renewable Heat Incentive (RHI).

Domestic RHI is no longer available in Northern Ireland. Details of the previous scheme can be viewed at NI Direct.


If you’re planning to install an air source heat pump in your home, you need to register the energy device with your Distribution Network Operator (DNO). The DNO is the company responsible for bringing electricity to your home. Usually, your installer will register the device for you.

The UK Government has advice on how to register your new energy device in England, Scotland and Wales.


Heat pump systems typically come with a warranty of two to three years. Workmanship warranties for heat pumps can last for up to 10 years, for example, through Quality Assured National Warranties (QANW). Many manufacturers also offer options for warranty extensions for a fee.

With regular scheduled maintenance, you can expect an air source heat pump to operate for 20 years or more.

Every year, you should check that the air inlet grill and evaporator are free from leaves or other debris. Remove any plants that start to grow near the heat pump. You may also be advised by your installer to check the central heating pressure gauge in your house from time to time.

Ask your installer for written details of any other maintenance checks you should undertake to ensure everything is working properly. Consult with your supplier for exact maintenance requirements before you commit to installing a heat pump.

A professional should service the heat pump every two to three years.

Planning permission

Before starting, check if you need to apply to the relevant planning authority for permission for the siting and external appearance of the air source heat pump.

Find out more about getting permission.

Last updated: 15 September 2021