Ground source heat pumps use pipes which are buried in your garden to extract heat from the ground. When the sun shines on the ground its heat energy is absorbed into the ground. Ground source heat pumps extract this energy. 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. The energy produced can be used to heat radiators, under-floor or warm air heating systems.