A heat pump is a device that 'pumps' or transfers thermal energy from one source to another by using a compressor and a circulating structure of liquid or gas refrigerant, through which heat is extracted from external sources and pumped internally.
Air source heat pumps absorb heat from the outside air to heat your home and hot water. They can still extract heat when air temperatures are as low as -15°C. This type of heat pump converts solar energy stored in the air into energy, transferring that heat energy to the heating and hot water circuits of the house.
A ground source heat pump circulates a mixture of water and antifreeze around a ground loop, which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump, which can then be used for the heating and hot water circuits of the house.
A water source heat pump uses the natural heat that’s present in lakes, ponds, rivers and springs. This heat is then transferred to the heat pump through a heat exchanger, which then can be used to heat the hot water and central heating systems in your house.