Heat pumps are reverse cycle air conditioners. Heat pumps use a complete cycle system to supply heat or remove heat from a temperature controlled space. Heat pumps contain a valve that enables them to switch between air conditioning and heating. There are many types of heat pumps. Examples include an electric heat pump and a geothermal heat pump. An electric heat pump is a year round comfort conditioning heat pump system that uses a refrigeration system, which provides warm and cool air using electricity with proper back up systems. A geothermal heat pump relies on heat produced inside the earth, which is stable and even. A geothermal heat pump can be used to provide heating, air conditioning, and obtaining hot water. Heat pumps have an individual heat pump rating, heat pump efficiency, and heat pump cost. Other types of heat pumps are commonly available.

There are several ways in which heat pumps function. Heat pumps use external work to extract an amount of heat from a cold reservoir and deliver it to hot reservoir. The heat pump rating of an electric heat pump lies between the ranges of 95% to 100% with a heat pump efficiency of 90%. Even though the heat pump cost of an electric can be high, it is still 24% less than other types of heat pumps. A geothermal heat pump uses the heat inside the earth and transfers it to houses. The cost of a geothermal heat pump is about $2,500 per ton of capacity. A geothermal heat pump has a heat pump rating of 10.0 to about 17.0. The heat pump efficiency of a geothermal heat pump system is 80% and can be maintained properly by regular inspection of the heat pump system. Heat pump repair is essential at frequent intervals for the cleaning of dirty filters and clogged burner ports. For the proper working and settings of a machine, heat pump repair must be done by a qualified technician. The efficiency of heat pumps can be drastically affected if yearly inspection of the machine is not performed.

Heat pumps are used in many applications. Examples include well water pumps used in the agricultural industry, heat pumps used in machines in factories, geo-heat centers, and pumps in swimming pools and spas. Heat pumps should adhere to Hydrologic Simulation Program (HSPF) standards.