Heat pumps extract heat from the environment with the help of a refrigerant – Luft, water or soil – Warm and heat the water via a heat exchanger, circulating in the heating circuit. For this process to work, electricity is needed, and all the more so, the greater the temperature difference between the energy source and the heating circuit. Good heat pumps achieve a coefficient of performance between 3 and 5: The amount of heat produced is three- up to five times as high as the power consumed. With the ground source heat pump, on a surface, which is about twice as large as the living space to be heated, Plastic pipes laid in the ground.