Air source heat pumps absorb heat from the outside air. This heat can then be used to warm water for radiators and underfloor heating systems or to warm the air in your home.

An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. Air source heat pumps can extract heat from the air even when the outside temperature is as low as minus 15 degrees centigrade.

The efficiency of an air source heat pump system is measured by a coefficient of performance (CoP) – the amount of heat they produce compared to the amount of electricity needed to run them. A typical CoP for an air source heat pump is around 2.5 meaning it generates 2.5 times the amount of heat per unit of electricity.