The outdoor units of heat pumps for private households are usually in the format of a large refrigerator. Depending on the type, they extract energy from either the water, soil or ambient air, which is used for heating. The supplier Sachsenenergie, on the other hand, sets it up a little larger. He plans to build a large heat pump in Dresden by 2031. The format: 50 x 35 x 18 meters (length, width, height).