A heat pump heats indoor spaces by pulling heat from the outside air into the indoor air. They can be switched into reverse to move heat from the indoor air into the outdoor air to cool down the indoor space. A compressor, which evaporates and condenses refrigerant, enables the transfer of heat from one space to another. Unlike an electric heat pump which uses an electric motor to power the compressor, a GHP uses clean burning natural gas in a combustion engine to drive its compressor.

The GHP utilizes scroll compressors combined with state of the art electronic controls and variable refrigerant volume management systems which allows up to 17 independent zones for the 8-ton and 33 independent zones for the 15-ton GHP. The use of a refrigerant loop eliminates the need for space consuming duct soffits and allows for the placement of air handlers within each dedicated zone. The GHP uses R-410A, one of the most environmentally-friendly refrigerant.