Cheaper to run and greener alternative to traditional heating systems
Heat pumps take heat energy from outside the home (from the air, the ground or even from water). This heat energy is then concentrated to provide heat for your home at temperatures that can be used for radiators, underf loor heating, warm air convec tors and hot water. Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the environment is constantly being renewed naturally.
How do they work?
An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. A fan helps to draw fresh air into the heat pump unit. It can get heat from the air even when the temperature is as low as -15°C. A ground source heat pump extracts heat from the ground via pipes, called a ground loop, buried in your garden. The ground stays at a fairly constant temperature under the surface all year round. The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead. Heat from the air or ground is absorbed into a special material (a refrigerant) thus raising its temperature. The pump in the system compresses the refrigerant to raise its temperature even more, and this useful heat is then transferred into your central heating system to warm your home and into your tank to heat your water.
What do I need?
It is essential that your home is well insulated and draughtproofed for a heat pump system to be effective, so plan energy efficiency improvements first. A well-insulated home with a lower demand for heat will also mean that the size of the heat pump required will be smaller and, therefore, cheaper. Unlike traditional boilers and electric storage heaters, heat pumps deliver heat at lower temperatures over much longer periods. Heat pumps are most efficient when used with larger radiators or underfloor heating. If you have standard radiators designed for a traditional boiler then your heat pump installer should tell you whether you are best to replace them with larger radiators to get a more efficient system that is cheaper to run. We recommend you use an installer approved under the Microgeneration Certification Scheme (MCS) and you get quotes from at least three installers to compare costs and services.
How much do they cost?
A typical domestic air source heat pump system costs from £7,000 to £13,000 to install, or from £13,000 to £20,000 for a domestic ground source heat pump system. Costs will depend on the system type, the property and the location.