Air conditioning ban on UK homes: what the rules really mean

Twenty percent of UK homes already exceed 26°C in summer, according to the Climate Change Committee. By 2050, that figure could double. Yet a rumour is circulating that the government plans to ban air conditioning in new homes entirely.

As reported by the Big Issue, the claim stems from a misreading of Part O of the Building Regulations, introduced in 2022. The regulation does not ban AC. It requires developers to demonstrate that passive cooling, shading, ventilation, insulation, has been optimised before installing mechanical systems. The rule is about hierarchy, not prohibition.

What Part O actually says

Part O applies to new homes and major renovations. It sets two compliance routes: a simplified method using fixed glazing ratios and shading, or a dynamic thermal modelling approach. Only if these fail to keep indoor temperatures below 26°C for more than 1% of occupied hours can mechanical cooling be added.

For existing homes, there is no restriction. Any homeowner can install a window unit, portable cooler, or split-system AC tomorrow. The catch is cost. Running a 2.5 kW AC unit for 8 hours a day over a 30-day heatwave adds roughly £90 to an electricity bill at current price cap rates (24.5p/kWh). That’s before the £1,500–£3,000 installation cost for a permanent system.

But the bigger issue is efficiency. A typical air conditioner has a Seasonal Energy Efficiency Ratio (SEER) of around 3.5, it moves 3.5 units of heat per unit of electricity. A heat pump in cooling mode achieves a SEER of 4–6. So a heat pump can cool your home for roughly 30% less electricity than a dedicated AC unit.

Why the rumour took hold

The confusion stems from a 2023 consultation by the Ministry of Housing, Communities and Local Government, which proposed tightening Part O to discourage AC in all but the most extreme cases. Some media outlets interpreted this as an outright ban. It isn’t. The consultation closed in March 2024 and no changes have been enacted.

What this misses is the real problem: UK homes are not designed for a warming climate. The average new-build has floor-to-ceiling glazing on south-facing walls and minimal external shading. Even with trickle vents, internal temperatures can hit 30°C in July. Part O is a sensible attempt to force developers to think about orientation, overhangs, and reflective coatings before defaulting to AC.

For homeowners, the lesson is clear: passive measures first. External shutters cost £200–£400 per window and can reduce solar gain by 80%. Loft insulation (270 mm minimum) keeps heat out in summer as well as in winter. A whole-house mechanical ventilation system with heat recovery (MVHR) can cool incoming air by 3–5°C without running a compressor.

What it means for your EPC and bills

Installing AC does not directly affect your Energy Performance Certificate rating. The EPC measures energy efficiency, not cooling capacity. But adding a high-consumption appliance can lower your rating if it increases your total energy use without corresponding insulation improvements.

The Energy Saving Trust advises that a home with an EPC band D or lower should prioritise insulation and draught-proofing before considering any cooling system. A well-insulated home can stay 3–5°C cooler than a draughty one during a heatwave, without any mechanical help.

If you do need cooling, a heat pump is the smarter choice. It qualifies for the Boiler Upgrade Scheme grant of £7,500 (until March 2028) and can both heat and cool your home. The same unit that keeps you warm in January can reverse cycle in July. Running costs for cooling via a heat pump are typically £60–£80 per heatwave month, versus £90–£110 for a dedicated AC unit.

Households on standard variable tariffs can apply for the grant through gov.uk from 4 November. Eligibility closes on 31 March 2027. Check your EPC first, it must be valid and show no outstanding recommendations for loft or cavity wall insulation.