As part of an extensive refurbishment the new owners of this semi-detached urban home replaced their gas boiler with an air source heat pump and installed a PV array to help offset the cost of operating it.

We installed an 8kW NIBE F2040 heat pump against the wall of a brick shed in the rear garden. We connected it to the heating and hot water system in the house using a continuous run of pre-insulated solarflex pipe which runs through the shed and up the wall of the house inside a 4” black plastic soil pipe.

To free-up space internally, we installed a 200L mains pressure horizontal hot water cylinder in the roof. The heat pump also supplies space heating to a UFH manifold on the ground floor and a radiator circuit on the first floor at a design flow temperature of 40°C.

The electricity consumed by the heat pump is partially offset by the energy generated by a 4.26 kWp PV array mounted on the south facing roof. This further reduces the estimated cost of operating the heat pump, ~3.9 versus 4.2 p/kWh for a gas boiler operating at 90% efficiency.