Almost every home in England will need air conditioning in the next few decades, even as planning rules block installations.
A new government report says 90pc of homes will need to install the technology by 2080 as climate change pushes temperatures ever higher.
Already 4.6 million properties are being hit by stifling summer overheating – especially people living in flats and mid-terrace homes in English cities, the report says.
Those numbers will surge as temperatures rise, with air conditioning being the only practical solution for most buildings, warned the study, commissioned by the Department for Energy Security and Net Zero (DESNZ) from consultancy LCP Delta.
The findings could force a major rewrite of current building codes, which mandate that homes should be cooled by passive measures such as insulation, shading and window modifications whenever possible.
However, the report warns that these measures will never cope with the kinds of heatwaves expected as climate change progresses. Only active air conditioning will be able to keep many homes at a safe temperature, it warns.
DESNZ’s warning clashes with UK building regulations, which favour passive cooling measures over air conditioning.
It warned that adapting to a warming world meant scrapping rules requiring owners of commercial properties and some blocks of flats to obtain full planning permission before installing air conditioning – often refused by local authorities.
Homeowners have faced obstacles to installing air conditioning units, with some councils telling residents to remove units for breaching climate change rules.
Academics have also come under fire for suggesting the UK will need air conditioning in future, with critics saying the technology makes cities hotter.
However, the DESNZ report states: “UK buildings have been traditionally designed for winter warmth rather than summer cooling, but overheating is already a problem in some, and this is expected to get worse as temperatures rise.
“In a scenario with temperature rises of 2C by 2080, none of the buildings outside Scotland passed the overheating risk assessment.
“In a scenario of +4C warming 90pc of all UK dwellings will need some type of active cooling solution to mitigate against overheating.”
Since the 1980s, the UK has warmed at about 0.25C per decade, in line with rising greenhouse gas levels in the atmosphere.
Met Office data suggest that, so far, average UK temperatures have risen by just under 1.5C compared to the middle of last century.
