Ground Source Heat Pumps (GSHPs)
Ground Source Heat Pumps extract energy from the ground and concentrate it to pump heat around a central heating system. Compared to electric heating they use around a third of the energy but they are very expensive to install and can only be classed as renewable energy if you have a green electricity supplier. They work best with under-floor heating but special low temperature radiators can be used (see www.purmo.com). The system also needs to b e installed in a well insulated building, and well-designed and controlled. RHI payments will be available.
Air Source Heat Pumps (ASHPs)
Air source heat pumps (ASHPs) extract energy from outside air (even down to a temperature of minus 20°C), and concentrate this energy to pump heat around the home. They are cheaper to install than GSHPs but generally have a lower efficiency and perform better in more temperate conditions (i.e. not too cold). Large ASHPs can run a whole central heating system, including hot water, whilst smaller ones can provide heating for just one room. If you intend to buy an ASHP, choose a model with an inverter (these are quieter and more efficient), and do not be tempted to use them for air conditioning as doing so would increase your energy consumption significantly. RHI payments are available for ASHP installations providing they are attached to a radiator system. Air to air systems are not eligible.
Please note that if heat pumps are poorly matched to a property with inadequate insulation, you risk increasing your heating costs and carbon emissions. For further information you can contact our Energy Officers, or you can see a report on a heat pumps trial at http://www.energysavingtrust.org.uk/Generate-your-own-energy/Heat-pump-field-trial.