The UK Government has expanded the Boiler Upgrade Scheme (BUS) to include air-to-air heat pumps, in recognition of their role in cutting energy use and carbon emissions in off-gas and all-electric homes.
While both air-to-air and air-to-water heat pumps extract heat from the outside air, the key difference lies in how that heat is delivered. Air-to-water heat pumps feed into a wet heating system with, for example, radiators or underfloor heating. For monoblock units, all refrigerant is sealed within the outdoor unit, so installers do not require F-gas qualifications.
In contrast, air-to-air heat pumps distribute heat via indoor fan units, with refrigerant carried in pipework between the indoor and outdoor units. This means installations must be carried out by F-gas-qualified engineers, creating new training and business opportunities for installers, particularly in urban areas dominated by flats or rural, off-gas properties.
Air-to-air systems typically do not produce domestic hot water and cannot be installed in kitchens or bathrooms without ducting, but they offer a highly efficient alternative to electric storage heaters and direct-electric systems. Typically operating at high efficiencies, they can reduce running costs significantly while supporting the Government’s wider electrification strategy.
Their lower installation cost is reflected in the £2,500 BUS grant, compared with £7,500 for air-to-water heat pumps. This makes them a practical option for smaller properties and apartments that lack wet heating systems.
Kevin Lowe, Technical Manager at HHIC, said: “Air-to-air heat pumps offer another string to the bow for low-carbon heating. They won’t replace air-to-water systems in homes with radiators, but they provide a much better use of electricity in all-electric, off-gas homes.
“Including air-to-air in the BUS helps widen access to efficient, low-carbon heating and opens up new opportunities for installers with F-gas qualifications.”