Is Air Conditioning Banned in UK New Builds? The Net Zero Regulations Explained

What Part O actually requires

Part O - formally Approved Document O - applies to new residential buildings in England. It requires developers to assess and mitigate overheating risk at the design stage. The regulation establishes a hierarchy: passive measures such as shading, window orientation, cross-ventilation and thermal mass should be considered first. Only where these are insufficient may mechanical cooling be introduced.

This does not constitute a prohibition. It requires that air conditioning not be used as a substitute for poor building design. A new build that meets the passive cooling requirements of Part O can still include air conditioning as a supplementary system. The regulation is aimed at ensuring homes are designed not to overheat rather than at banning specific technologies.

The political debate during the June 2026 heatwave

The current heatwave has renewed a political debate about the affordability and accessibility of air conditioning for UK households. Conservative shadow energy secretary Claire Coutinho has argued that UK building regulations constitute a de-facto ban on air conditioning and has called for the rules to be revised. Building and energy experts have disputed this characterisation, noting that Part O allows mechanical cooling where passive measures are insufficient.

The confusion partly stems from the Boiler Upgrade Scheme, a government grant programme supporting heat pump installations, which does not cover air-to-air heat pumps. Air-to-air heat pumps can both heat and cool a property and are common in many countries. The exclusion from the BUS means homeowners seeking a combined heating and cooling solution via this technology cannot access grant support - a genuine gap in policy that critics argue discourages adoption.

How many UK homes have air conditioning

Approximately 5% of UK homes currently have some form of air conditioning, compared to around 90% in Japan and South Korea and 90% in the United States. The low UK penetration rate has historically reflected climate rather than regulation - the UK has been cooler than countries where air conditioning is near-universal. The Climate Change Committee has projected that 92% of UK homes face a risk of overheating by 2050 under central climate scenarios, suggesting the case for domestic cooling will grow materially over the coming decades.

What homeowners can do now

Homeowners in existing properties can install air conditioning without requiring planning permission in most cases, provided the unit is not installed on a wall or roof facing a highway and the building is not in a conservation area or listed. Permitted development rights cover most standard split-unit installations. Homeowners should check with their local planning authority if in doubt.

For new build buyers, any overheating mitigation measures required under Part O will be built into the property by the developer. If a buyer wishes to add supplementary mechanical cooling after purchase, standard permitted development rules apply in the same way as for existing homes.

Running costs of air conditioning

A typical domestic split-unit air conditioner draws between 1kW and 2.5kW of electricity depending on capacity. At the current Ofgem price cap electricity rate, running a 1.5kW unit for eight hours per day costs approximately £2.88 per day. Inverter-driven units are significantly more efficient than older fixed-speed models and can reduce running costs by 30-50% compared to less efficient alternatives.