A GAHP can be used in all types of houses, new and old. It is most suited to older houses with low efficiency rating (E-H) where there is limited scope for adding other renewable systems, like electric heat pumps or solar. It’s the perfect solution to add to an existing system with radiators and a hot water cylinder. Very new houses with full insulation (roof, windows, walls) and underfloor heating would benefit from an electrical heat pump, rather than a GAHP. The beauty of the technology in a GAHP is that it is designed to be retrofitted into existing, older properties.