Air Source Heat Pumps

ASHPs are powered by electricity and require a dedicated connection within the property.

The unit draws in air that is then passed over a refrigerant, which boils at around 40 degrees. The refrigerant gas is then compressed and passed over an evaporator which distributes the heat into a heat exchanger. This is known as the 'refrigeration cycle' and is exactly the same process that happens in domestic fridges.

Buffer tanks or volumisers are common with heat pump systems as heat pumps require a 'minimum system volume' to operate effectively and ensure that they can perform a defrost cycle to melt any ice build up. The defrost effectively reverses the operation and uses the hot water in the pipework to melt the ice.

Flow and return pipes are run into the house and connected to the space heating and DHW circuits, often via a buffer tank or volumiser. The pipework must be properly insulated and filled with glycol to prevent freezing in the event of a power failure or breakdown. Monobloc systems are perfect for heating engineers moving into heat pumps.

Split pumps have both an indoor and outdoor unit that are connected by refrigeration pipework. Outdoor units are generally a little smaller than other heat pumps, as they do not have any hydraulic components. The indoor unit contains the heat exchanger and pump and looks very similar to a gas boiler. With split systems, the outdoor unit can be installed up to 25m away from the property. Installers must be FGAS registered.

Hybrid systems utilise a heat pump alongside a traditional boiler. These can work as true hybrids, whereby both systems work at the same time to maximise efficiency, or as a bivalent set up, in which the system switches from the heat pump to the boiler at a pre-set temperature. One key advantage of this setup is that a combi boiler can be used to provide the hot water, removing the need for a heat pump cylinder to be installed.

Through our dedicated, in-house Energy Efficiency team, we can support you with: