Is it legal to install AC in the UK?
Yes, air conditioning is legal in UK homes. Two rules apply: an F-Gas certified engineer must do the refrigerant work, and the outdoor unit must either fall within permitted development or have planning permission. Since 29 May 2025, permitted development in England can cover a unit that heats as well as cools, within size and siting limits. Neither rule is a barrier; both are process.
The question comes up because people half-remember two real rules and merge them into a myth. There is no ban on domestic air conditioning anywhere in the UK. Millions of British homes and virtually every office you have worked in run it.
Rule one concerns who does the work. Refrigerants are controlled gases under the UK F-Gas regulations, so installing, commissioning or repairing the sealed refrigerant circuit is restricted to certified engineers. This is about preventing gas releases, not restricting cooling.
Rule two concerns the outdoor unit. In England, the permitted development right for air source heat pumps was amended on 29 May 2025 to cover units that are not used solely for cooling, on a house or on a block of flats, so a reversible split that heats in winter can qualify. In June 2026 the government said that in most cases a small home needs no planning permission if the unit does not materially affect the building's outside appearance. Listed buildings, conservation-area frontages and later units on a block of flats are the exceptions, and there a check with your borough is essential.
What is genuinely regulated more tightly is commercial buildings: systems over 12kW need periodic TM44 inspections, and new buildings face overheating rules under Part O that push developers toward shading and ventilation before cooling. None of that stops you cooling your bedroom.
More in rules, planning & flats, or browse all 40 questions on the FAQ index.
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