An air-water type heat pump extracts heat from the outside air uses it to heat water. This water can be used for both heating and domestic hot water. An air-water heat pump has several advantages. The most obvious is that air is available anytime, anywhere. This type of heat pump can also be combined with and existing central heating system with radiators. The heat pump with an air-water system is easy and inexpensive to install and is also placed outside so you don't lose space. You can also use these heat pumps with fan coil units and floor heating.