Air conditioning planning permission in England

If your home overheats in summer and you are planning air conditioning or an air-to-air heat pump to cool it, planning permission is the step people most often get wrong. Our overheating model scores a typical top-floor London flat around 60 out of 100, so the demand is real - but the rules for fitting an outdoor unit are specific, and they changed in 2025.

Since 29 May 2025, England's permitted-development rules let a house fit an air-to-air heat pump - which heats as well as cools - without a planning application in many cases, within set size, siting and noise limits. A cooling-only air conditioning unit does not get that route and needs a full planning application whatever the property, because on its own it only cools.

So the system you choose changes your planning path, not just your comfort. The same box that both heats and cools opens the permitted-development route on a house; a unit that only cools does not.

A full application is the likely route when the outdoor unit goes on a front or side elevation facing a road, when the property is a flat or maisonette, or when the home sits in a conservation area or is a listed building. Size and siting also matter: an outdoor condenser has to sit within defined bounds on the building and the plot, and exceeding them removes the permitted-development route even for a house.

Flats are the sharpest exception. Permitted-development rights for an outdoor unit sit with the house, and a flat does not get them the same way - the right effectively belongs to the whole building, so you will usually need both freeholder or managing-agent consent and planning permission. If you are a leaseholder, check your lease as well: many require landlord consent for any external alteration, quite separately from planning.

Many older and city-centre homes sit within a conservation area, and there the permitted-development route is tighter or removed, so an external unit on a visible elevation will usually need permission. Being close to a listed building is not the same as your home being listed - but where either genuinely applies, you will usually need to confirm the position, and sometimes listed-building consent as well, with your council.

Public data can flag these things but rarely settles them, which is why the honest answer is often to confirm with your Local Planning Authority before you commit.

None of this is a dealbreaker - councils approve outdoor units for homes like these all the time - but it is a step to plan for, not a formality. This is indicative guidance, not legal advice: confirm the final position with your Local Planning Authority (LPA) before you install.