Heat pumps

A heat pump extracts heat from its surroundings (the air, the ground or water) and, by compressing refrigerant in the compressor, raises it to a higher temperature suitable for space heating and hot water – much like a pump inflating a bicycle tyre. It can obtain heat even from air at –20°C, although this process is slightly less efficient.

Air-to-water heat pumps are popular thanks to their simple installation, as no boreholes or ground collectors are needed. Ground-to-water heat pumps, by contrast, are the most efficient, but their higher investment cost limits their use – even so, the ground maintains a stable temperature of around 10–12°C from just 10 metres below the surface.