FAQ: Answer

How do Air Source Heat Pumps work?

An ASHP uses energy from the outdoor air. Air is pulled across a heat exchanger inside the heat pump where the energy is extracted by refrigerant gases. These gasses are compressed via a compressor to give useable heat.  This heat is transferred to your heating system in the same way as a conventional boiler sends heat to your radiators, underfloor heating or hot water cylinder so it is ready whenever it is needed.

More Questions About Air Source Heat Pumps

How much will an Air Source Heat Pump installation cost?

An example of a typical 3-bedroom detached bungalow that has an oil boiler and 9 radiators will cost approximately £18,000 to change the heating system to Air Source Heating.

You could expect to receive government grant of £5,000 through the Boiler Upgrade Scheme (BUS).

It is estimated you would benefit from fuel savings each year, depending on your current electricity provider unit rates.

The costs involved in installing a system include the following:

  • Removal of the existing system.
  • Custom design of a heating system for your property.
  • Installation of the air source heat pump (unit fitted outdoors).
  • Installation of a new cylinder that has an increased size primary coil fitted.
  • Installation of a buffer vessel (another cylinder for the heating system fluid).
  • Replacement of the radiators with new, larger radiators.
  • Replacement of the current heating controls.
  • Electrical wiring of the new system. Often a new supply will need to be run from the consumer unit to the outdoor air source heat pump.
  • Plumbing required to adapt the old heating and hot water systems to the new heat pump and radiators.
  • Registration and certification for Microgeneration Certification Scheme so that you will be eligible for the Boiler Upgrade Scheme.

Do I need to upgrade my fuse board to install a heat pump?

Generally speaking your fuse board would need to be 80amps to 100amps for an air source heat pump.

UKPN provide guidance on fuse upgrade criteria and which components are owned by either the property owner, electricity supplier and or installation company.  You can find the UKPN fuse upgrade criteria guide here.


Will an Air Source Heat Pump still work when it is freezing or snowing outside?

Absolutely. We design your heating system to be able to provide 21 degrees to the living areas of your property when it is sub zero temperatures outdoors. The refrigerant in the ASHP is designed to work down to -10 degrees and beyond.

How much does an air source heat pump cost to run?

Air source heat pumps are effectively the cheapest form of heating to run. They can be 300 – 400% efficient or more.

A ground source heat pump generates 3-4 times the energy it consumes. This means that for every 1kw of electricity that you pay for, a GSHP can produce 3-4kw of heat for your home.

Will I have lower energy bills if I install an ASHP?

If you are changing from LPG, oil or direct electric there are considerable savings to be made in your annual running costs.

An air source heat pump generates 3 times the energy it consumes, this means that for every 1kw of electricity that you pay for, an ASHP can produce 3kw of heat for your home.

How energy efficient is an Air Source Heat Pump?

An Air Source Heat Pump works at a minimum of 300% efficiency, compared to around 90% for oil boilers and 92% for modern condensing gas boilers. Therefore your EPC rating will improve, you will be using less CO2 due to the increased efficiency of your heating system and reducing the use of fossil fuels.

Does the government offer incentives to install an ASHP?

The government currently offers the Boiler Upgrade Scheme which offers a £5,000 grant towards the installation of an air source heat pump.  This grant is available until 31st March 2025. Full up to date information on the current schemes and eligibility is available and detailed on our Incentives page.

Can I use my existing radiators with a new Air Source Heat Pump?

If the radiator in a room is sized correctly for that room and currently being heated by a gas or oil boiler, then it is not likely to be suitable to be used with an ASHP.  A new radiator sized correctly to work with an air source heat pump will be needed.

What size air source heat pump do I need to heat my home?

The size of heat pump you need depends on many factors.  R A Brown will complete full heat loss calculations and then we can make a recommendation for your property.  The size and age of the property, the insulation levels and the type of heat emitters (underfloor heating/radiators) you choose will also have an impact on the size of air source heat pump you need.


How many years will my ASHP run for?

The external unit is expected to last up to 20 years on a system which has been designed and installed correctly.



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