An electric heating element normally has a performance efficiency of one, meaning that for every kilowatt of electricity input a kilowatt of heat is output. A heat pump, however, has a performance efficiency of between two and four. The vapour compression cycle moves heat from one area to another and for one kilowatt of compressor effort, two to four kilowatts of heat are moved.
Air source heat pumps operate on average with a performance efficiency of 2.5, as it is difficult to extract heat from a very low temperature source, such as -4ºC in winter.
Ground source heat pumps using water from a borehole or a closed loop routed through the earth could have 16ºC available as a heat source year round therefore performance figures of 3.2 are not uncommon.
Air source heat pumps are an extremely affective method of extracting heat from exhaust air and can be utilised in buildings across all sectors.