Ground Source Heat Pumps

How do they work?

The earth stores an enormous amount of solar energy from both solar radiation and rainfall. To extract this energy, ground collectors consisting of flexible poly ethylene pipes are buried in the earth. A mixture of water and anti-freeze is then circulated through the pipe loops, attracting the heat energy and transferring it to the heat pump. This can be done using two different methods: Bore Hole or Slinky. See below for more information.

Bore Hole

If land space is limited the ground collectors can be installed vertically in a borehole, drilled up to 100m deep in the ground.

Multiple boreholes are commonly used in large installations where very high levels of heat extraction are required.


If a large enough land area is available, horizontal ground collectors provide an effective method of extracting heat from the ground. The pipework is buried at a depth of approximately 1.25m and spaced 0.75m apart. The land area required is dependant on both the capacity of the heat pump and heat conductance of the soil type in which the pipes are buried.

As a space saving alternative to horizontal collectors, slinkies – consisting of coiled pipes buried in a trench – can be used.