A ground source heat pump (GSHP) is a central heating and/or cooling system that pumps heat to or from pipes buried in the garden. It uses the earth as a source of heat in the winter and as a source of cold in the summer. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home.
A GSHP circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year.
The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical geothermal borehole can be drilled instead.
The setup costs of installing a GSHP are higher than a conventional system, but the difference is usually returned in energy savings between 3 to 10 years. System life is estimated at 25 years for inside components and 50+ years for the ground loop.