The younger sibling of the ground source heat pump (GSHP), the air source heat pump (ASHP) is an exciting development in heating technology. They operate on the same principles as the under-ground alternative, but draw thermal energy from the air rather than underground – air at ambient temperatures is passed over a finned heat exchanger and heat energy extracted into the evaporator of the heat pump. ASHP’s release up to four times more heat energy than they consume in powering their various components and so offer an energy efficient, sustainable heating solution. They are best coupled with well insulated, energy efficient buildings and under floor heating systems.
Currently (summer 2007), a 6kW ASHP costs around £3,500 with a larger 12kW pump weighing in at about £6,000. This excludes the cost of the distribution system such as an under floor heating installation.
As air is the medium from which thermal energy is extracted, the installation of an ASHP is relatively straightforward – there is no need to dig extensive trenches or drill the borehole necessary for a GSHP. The pump is sited at a suitable distance from building and connected via pipe work buried in trenches. ASHP’s are designed to operate with minimal noise pollution.