Air-to-air heat pumps also transport and compress heat from the air outside, but transfer it to a home as blown air. This negates the need for radiators or underfloor heating, as well as enabling their use for cooling. They are considered to have similar energy efficiency to air-to-water heat pumps, although there is little evidence of this in practice. They consist of a smaller outdoor fan unit with indoor units for each heating zone. They are not able to produce hot water and so require a separate technology, such as an immersion heater, alongside it.

They are often mislabelled as air conditioning in the UK and are most commonly used for commercial premises. In Scandinavian countries, they are typically used with other supplementary heat sources or to serve as a source of cooling in countries like Spain. Air-to-air heat pumps may be a good option for smaller properties and flats. Currently, they are not eligible for the Boiler Upgrade Scheme.

The cost to install a single unit to cover a single heating zone can be even lower. Some households could install air-to-air heat pumps whilst retaining their previous heating system. This means that they can be very affordable in small homes, especially studio flats, but costs rise sharply for larger homes. They should have similar efficiencies to air-to-water heat pumps, but this is not well documented in the UK. Installation disruption may be 2 to 3 days.