A few metres down the ground stays at a constant temperature about 10 to 15 degrees in the United kingdom. The heat can be transfered to your home using a ground source heat pump. Ground Source Heat pumps draw heat from the ground via a ground collector (slinky) or a ground probe (bore hole).

Heat pumps work in much the same way as a fridge but in reverse. In a fridge the heat is transported from inside to outside, while a heat pump takes heat stored below the underground frost line and transports it via the heating system to the house interior. Some systems are designed to work in reverse as well, cooling the interior in hot weather.