Ground Source heat pumps use pipes (loops) buried in the garden to extract heat from the ground. Beneath the surface the ground stays at a constant temperature so a ground source heat pump can be used throughout the year – even in the middle of winter.

A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe (called a ground loop) which is buried in the garden. When the liquid travels around the loop it absorbs heat from the ground which can be used to heat radiators, underfloor heating systems or hot water.

The length of the loop depends on the size of the property and the amount of heat you need – longer loops can draw more heat from the ground. Normally the loop is laid flat or coiled in trenches about two metres deep however if there is insufficient space a vertical loop can be installed in a bore hole to a depth of about 100 metres.

The efficiency of a ground source heat pump system is measured by a coefficient of performance (CoP) – the amount of heat they produce compared to the amount of electricity needed to run it. A typical CoP for a ground source heat pump is around 3.2 meaning it generates 3.2 without any reductions for the type of distribution system.