Air Source Heat Pumps

Air source heat pump diagram

An air source heat pump is located on the outside of your home and connects to the heating system inside. If your home is particularly well ventilated, the air source pump can replace the central heating boiler.

How do they work?

Air source heat pumps harness the heat from the air outside. They can operate in temperatures as low as -15 degrees and so remain very effective all year round. In residential properties, these systems are particularly effective for underfloor heating as it is a lower temperature system, but they can suit and heat most houses, regardless of the type of property.

These type of pumps are particularly suited to areas that have no mains gas supply and they are more economical to run than oil central heating. Because of their method of heating air, they are also a highly eco friendly choice of energy. If you already have an oil fired boiler, you can add an air source heat pump easily to improve efficiency and cost of your existing system.

Heating and cooling air is achieved by passing a refrigerant through coils which are indoor and outdoor components. The refrigerant is changed from liquid to hot gas through the use of a condenser, compressor, valve and evaporator.

Once the vapour enters the compressor, its temperature increases to more than 100 degrees. It then passes through the coils and transfers to a liquid. The cycle then repeats itself.

The heat from the pump is transferred efficiently into your hot water tank and underfloor or central heating system.


Air source heat pumps are very cost effective options, when compared to most other energy alternatives such as gas, oil and electric. The government’s renewable heat incentive scheme also benefits owners of air source heat pumps, with subsidies available.

Air source pumps are eco friendly, unlike oil, gas and LPG. Photovoltaic panels can be used with them, making them carbon neutral and eligible for the Feed in Tariff scheme.

No large storage tanks or boilers for biomass fuels are needed, thus saving on space considerably. You do not need to store combustible fuels at your property and as there are no harmful emissions, air source pumps do not need flueing.

Maintenance is minimal, as the pump has a similar mechanism to a refrigerator. You simply need to ensure the unit is kept clean from leaves and other debris.

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