Most heat pumps operate on a circuit of creating a pressure that allows it to push heat from one area to an area far away from the main unit generating the heat. Different heat pumps operate in different ways but do follow a very similar principal. The Ground Source Heat Pump pumps air generated from under ground, a sort of thermal dynamics that the earth puts off. It is an efficient system that essentially recycles the heat that doesn’t escape from deep down under the soil. cold weather doesn’t usually penetrate to the area where this heat is and thus this system is great for sub zero temperature climates.