Do You Need Planning Permission for Air Conditioning in the UK?
For a portable unit vented through a window you can already open — the kind covered across this site — the answer is simple: no permission of any kind, because nothing is installed or altered. Planning only enters the picture for a fixed installation with an outdoor condenser. That may fall under permitted development, but with conditions on size, siting and noise — and those rights are removed for listed buildings, conditioned in conservation areas, more limited for flats, and can be withdrawn by an Article 4 Direction. We deliberately don’t quote the size and distance figures here, because published sources disagree and only your LPA can confirm the current ones.
Most people asking this have a portable unit in mind and don’t need permission at all. The rest of the page is for anyone considering something fixed.
Portable units: nothing to apply for
A portable air conditioner vented through an opening window installs nothing and alters nothing. There’s no external unit, no penetration of the structure, no change to the building’s appearance.
So there’s no planning question. The only things to check are practical or contractual — whether you rent (a portable unit is normally fine, but read your agreement), and whether a lease restricts appliances. Our renter’s guide covers that.
Fixed installations: where planning applies
A wall-mounted split system has an outdoor condenser unit, and that’s what planning is concerned with — an addition to the outside of the building.
In England, installing an outdoor air conditioning unit on a house can fall within permitted development, meaning no full application is needed — provided a set of conditions is met. The conditions typically cover things like the size of the unit, how close it sits to a boundary, its position on the building, and noise.
The conditions everyone agrees on
Regardless of the exact figures, these apply and are well established:
- Listed buildings have no permitted development rights for this. You’ll need listed building consent, and unauthorised work is a criminal offence, not merely a planning breach. Our heritage guide covers it.
- Conservation areas carry extra conditions — commonly that an outdoor unit must not be placed on a wall or roof that fronts a highway.
- Flats and maisonettes are treated more restrictively than houses; permitted development for this is generally more limited or unavailable.
- An Article 4 Direction can remove permitted development rights in a defined area — check whether one applies to your street.
- Noise conditions apply, and separately a neighbour can raise a statutory nuisance complaint with the council regardless of planning status.
- The devolved nations differ. Scotland, Wales and Northern Ireland have their own regimes — don’t assume the English position applies.
Leasehold: a separate permission entirely
Worth stressing, because people conflate the two: planning permission and your freeholder’s consent are different things, and you may need both.
Even where an installation is permitted development, in a leasehold flat the freeholder controls the structure and exterior. Fixing a condenser to the building almost always needs their written consent under the lease, often via a formal licence to alter — independent of whatever the planning position is. Our leasehold guide covers that process.
Building Regulations are also separate
Planning governs whether you can put the unit there. Building Regulations govern how the work is done — electrical safety (Part P), and the refrigerant work itself.
Refrigerant work requires certification. For fluorinated refrigerants that’s F-Gas certification; note that R290 is a hydrocarbon and falls outside the F-Gas regime, so ask specifically about competence with A3 flammable refrigerants. Our installation law guide and R290 guide cover this.
How to check properly
- Planning Portal first — it sets out permitted development for air conditioning and links the interactive guidance.
- Check whether your property is listed, in a conservation area, or subject to an Article 4 Direction — your LPA’s website usually shows this.
- A pre-application enquiry to the LPA, or a Lawful Development Certificate application, gets you a written answer specific to your property. The certificate isn’t compulsory but it removes doubt and reassures a future buyer’s solicitor.
- Ask your installer — a competent one deals with this routinely and should know the local position.
- If leasehold, ask the freeholder in parallel.
Frequently asked questions
Do I need permission for a portable unit?
No. Vented through an opening window, it installs and alters nothing. There’s no planning dimension at all.
What size outdoor unit is allowed without permission?
There are conditions on size and siting, but the exact figures are set in legislation that’s amended over time and the sources we found disagreed — so check the Planning Portal or your LPA for the current numbers rather than trusting a figure from a blog.
My neighbour objects to the noise. Can they stop it?
They can raise a statutory nuisance complaint with the council, which can act regardless of planning status. Siting and a quiet unit reduce the risk. It’s worth discussing before installing.
Is a Lawful Development Certificate worth getting?
It’s not compulsory, but it gives you written confirmation the work is permitted — useful in a conservation area, and reassuring to a buyer’s solicitor when you sell.
Sources
- Planning Portal — Do you need permission?
- Planning Portal — Air source heat pumps and outdoor units
- GOV.UK — When is permission required?
- GOV.UK — Approved Document P: Electrical safety
- GOV.UK — Fluorinated gases (F-gases): rules
- Leasehold Advisory Service — LEASE
Related reading: our installation law guide and listed buildings guide.
A portable unit vented through a window needs no permission. Compare current specifications at Amazon UK.
