The technology inside an air source heat pump is similar to any domestic refrigerator, which uses a vapour compression cycle. The main components in the heat pump are the compressor, the expansion valve and two heat exchangers.

Heat pumps move heat in the air into the home to provide a total solution for Domestic Hot Water (DHW) and all heating needs. Because heat pumps simply move energy, rather than creating it by burning fossil fuels, they are very efficient. For every 3KW of heat moved into the house only 1KW of electricity is consumed. This gives a perceived efficiency of 300% sometimes stated as a Co-efficient Of Performance (COP) of 3:1.

Heat collection is achieved by using a fan to force air, over a heat exchanger (simply a copper coil filled with refrigerant) to extract heat fro the air.

The purpose of the Evaporator is to take heat obtained by the heat exchanger and boil a refrigerant (which boils at approximately -10°C), the act of boiling turns the refrigerant into a vapour which is then moved into the Compressor.

The Compressor does exactly what its name suggests; the vapour is compressed in volume and as its volume reduces its temperature increases. Temperatures of between 75°C and 125°C are achievable and the gas is then fed through a heat exchanger.

Forcing the hot gas across the cold water from the central heating system condenses the refrigerant turning it back into a liquid. As it condenses its heat is passed into the heat exchanger which supplies the DHW and central heating system.

To complete the closed circuit of the heat pump the only thing which needs to be done is reduce the pressure of the condensed liquid and this is done via an Expansion Valve