A heat pump is a machine that collects low grade (or low temperature) heat energy from the outside air, ground or a body of water, and converts it into high grade heat which can be used in home heating systems and for hot water generation.

The heat pump uses the refrigeration cycle and some clever electronics to collect and transfer the heat as efficiently as possible.  With advances in compressor and refrigerant technology, heat pumps are getting more and more efficient.

Broadly speaking, yes.  In this analogy, the interior of the fridge would be the outside air or ground, and the warm back of the fridge the heating system.

The CoP is simply the ratio of electrical power input to heating power output.  If a heat pump is operating at a CoP of 3, for every 1kWh of electricity you put in, you get 3kWh of useful heat out.  The often quoted SCoP (Seasonal) is different: this is the CoP you can expect over the heating season, according to the manufacturer.

It’s not quite that straightforward.  A heat pump system will require a suitable hot water cylinder, and possibly other equipment such a heating interface unit and a buffer tank.  If the property is heated by radiators these will most likely have to be resized to give enough heating output, or replaced with Underfloor heating, as heat pumps only operate efficiently at lower flow temperatures than gas boilers.

Modern houses with high insulation values and air tightness are good candidates for a heat pump installation.  Older houses with poor insulation, draughty windows and doors and in exposed locations will require fabric upgrades in order to benefit.  Pure can advise on these measures.

It is possible to combine fossil fuel appliances with heat pumps, but the system needs to be carefully designed.  Simply putting a gas boiler on the same system will result in large inefficiencies and may well damage the heat pump.  A sizeable buffer tank and advanced controls will be required in order for the system to operate efficiently.

Generally heat pumps attract Local Authority  permitted development rights, however, certain installations may require planning permission.  (Refer to our ‘Approvals’ section). Again, PURE can assist with this process. See also *** Planning section…

Heat pumps use compressors, which do make some low level noise. They must be sited carefully to minimise the potential for unwanted disruption both at the property itself and its neighbours.

Generally, maintenance on heat pumps is minimal: the main requirements are a thorough inspection, cleaning and checking for refrigerant escape.

If you sell your property at any point during your seven-year membership you’ll no longer be eligible to receive Domestic RHI payments. You’ll need to let OFGEM know as soon as you decide to sell. They will issue your final payment up to the date that you leave the property and you will then no longer be part of the scheme. The new owner of your property is entitled to claim payments for the remainder of your seven-year membership, if they are eligible.