Air to Air Heat Pumps - What You Need to Know
Nesta Report: Are Air-to-Air Heat Pumps a Viable Alternative for UK Homes?
A recent report by Nesta — supported by Smart Projects' own Ashley Towndrow — takes a close look at the technical performance, deployment barriers and market potential of air-to-air heat pumps in UK homes. Ultimately, the core question is simple: can air-to-air systems offer a credible, scalable alternative to air-to-water heat pumps in the push to decarbonise domestic heating?
Air-to-Air Heat Pumps Can Heat Whole Homes
First and foremost, the report's standout finding is clear. Air-to-air heat pumps can deliver whole-home heating across a significant proportion of UK homes. Furthermore, when correctly specified and installed, these systems meet the heating demands of typical flats, terraced, semi-detached and detached properties. This directly challenges the assumption that air-to-air units only suit supplementary heating or cooling. Instead, the report positions them as a genuine primary heating solution.
Simpler, Less Disruptive Installation
In addition to strong heating performance, air-to-air systems are considerably simpler to install than wet heating retrofits. They need no radiators, no pipework upgrades and no large hot water cylinders. As a result, installation is faster, less disruptive and far more accessible. This is especially true in properties where space constraints make air-to-water systems difficult to retrofit. Consequently, for the UK residential HVAC market, this could meaningfully accelerate deployment and boost consumer uptake.
Efficiency That Competes with Air-to-Water Systems
Moreover, under the right conditions, air-to-air heat pumps achieve efficiency levels comparable to air-to-water alternatives. Property fabric, emitter layout and day-to-day usage all influence seasonal performance. That said, continuous, low-output operation consistently delivers the best results. Additionally, these systems respond quickly to changes in demand, making them well suited to zoned heating and the variable occupancy patterns common across UK households.
Which Properties Are Best Suited?
Of course, suitability varies by property type. Smaller homes and flats need fewer indoor units, which improves cost-effectiveness. Similarly, open-plan layouts benefit from better air distribution. Meanwhile, well-insulated new-build homes have lower heat demand, which boosts system performance and reduces equipment requirements. Overall, air-to-air heat pumps are particularly well matched to specific segments of the UK housing market.
Heating, Cooling and Air Quality in One System
Beyond space heating, air-to-air systems do much more. They also provide active cooling, dehumidification and air filtration. Given that summer overheating is a growing risk in UK homes, the report identifies cooling capability as a major added benefit. As a result, one system handles both heating and cooling, which strengthens the consumer case and further supports the broader electrification of domestic heating.
Limitations to Be Aware Of
However, the report is balanced and acknowledges real limitations. Most air-to-air systems do not provide domestic hot water, so properties will need a separate solution. Furthermore, outdoor unit placement, planning restrictions and leasehold rules can affect installation feasibility. In addition, strong performance depends on accurate system design, precise heat loss calculations and skilled installation.
Standards and Training Will Be Critical
Therefore, as the technology scales, robust standards, training and certification become essential. Without these, maintaining installation quality — and with it, consumer confidence and long-term decarbonisation goals — becomes increasingly difficult.
The Bigger Picture
Ultimately, Nesta concludes that air-to-air heat pumps are technically viable but under-recognised. They offer less installation disruption, flexible operation and integrated heating and cooling in one system. While they won't suit every property, they nevertheless represent a meaningful route away from fossil fuel heating.
To explore the full modelling assumptions, performance data, deployment analysis and policy implications, read the complete Nesta report.
