Martyn Bridges, Director of External Affairs, Worcester Bosch, takes a look at what installers need to know about air-to-air heat pumps policy:
As we navigate yet another summer of record-breaking temperatures, the conversation around how we heat (and now cool) our homes is shifting. For the second year running, we’re experiencing uncomfortably hot properties, leaving millions of homeowners searching for relief. The UK has not been a nation renowned for its residential air conditioning, as historically our climate simply didn’t warrant it, bar a few stray days in July. But the reality of climate change has caught up with us, with five of the hottest years in UK history occurring in the last decade.
Consequently, we are seeing meteoric growth in consumer demand for cooling systems as interest has spiked by several hundred per cent compared to last year. Many installers are now even finding it difficult to source the equipment needed to meet this sudden boom. We are currently experiencing the emergence of an entirely new residential market, which focuses significantly on a technology capable of performing both heating and cooling: the air-to-air heat pump.
Before looking at how we support this new market, it’s worth clearing up a common misconception that often hits the newspaper headlines. The government has not banned air conditioning in new-build properties. Instead, developers must comply with Building Regulation Part O, which addresses overheating. Local authorities also prefer passive design measures, such as external shading, window sizing and building orientation, as a first option before turning to mechanical cooling.
But this creates a contradiction. While Part O pushes designers to restrict solar gain, separate environmental mandates dictate the inclusion of solar PV panels in new homes. To maximise solar PV efficiency, you need a south-facing aspect, but this layout increases solar gain and, therefore, overheating. It’s a classic case of conflicting policy objectives leaving housebuilders and the installers working with them caught in the middle.
For installers, the real growth lies in the retrofit market. Retrofitting an air-to-air heat pump generally falls under permitted development, making it an easy sell. The only difficulty may be the occasional aesthetic objection from local authorities regarding outdoor units in conservation areas. The government has recognised the technology’s potential and introduced a £2,500 grant under the Boiler Upgrade Scheme (BUS) to incentivise installations.
Unfortunately, the criteria attached to this grant is fundamentally short-sighted. To qualify for funding, the system needs to provide both heating and cooling, with the property’s existing fossil fuel heating configuration, likely a boiler, being removed as a requirement. The incoming air-to-air system must heat or cool every room within the property.
In the real world, this presents significant practical challenges. Air-to-air heating is remarkably efficient, boasting a Coefficient of Performance (CoP) potential of five or more, meaning you get five kilowatts of heat out for every kilowatt of electricity put in, but they operate by blowing treated air. A standard setup would include one outdoor unit connected to one or two indoor units. To heat a traditional UK house, including every bedroom and bathroom, you would need to install between six or seven units. The structural disruption and cost would be immense, completely wiping out the value of the £2,500 grant. As well as this, an air-to-air heat pump generally doesn’t provide domestic hot water, meaning homeowners would have to get an entirely separate system, such as a heat pump cylinder, just to run their taps.
Because of these rules, it is likely we will see very few grants actually being issued for air-to-air technology. Homeowners simply want to retain their boilers and radiators for primary heating and hot water, with an air-to-air heat pump being used for zoning and cooling.
Current policy fails to recognise that air-to-air heat pumps are an exceptional supplement to traditional heating systems, rather than an all-or-nothing replacement. During the transitional months between autumn and winter, when a house needs just a small boost of warmth in the evenings, homeowners can run air-to-air heat pumps instead of firing up their entire central heating. This allows households to defer turning their gas boiler on for six to seven weeks of the year, significantly reducing fossil fuel consumption.
By demanding that a boiler be completely ripped out, current policies are policing an unrealistic ideal instead of helping with immediate carbon savings. Integrating air-to-air systems with existing boilers would unlock massive, rapid carbon reductions while giving homeowners the summer cooling it has become apparent they need. If the government wants to see clean heat policy truly succeed in practice, they must infuse some real-world flexibility into the BUS criteria and stop missing the open goal right in front of them.
