Do You Need Planning Permission for Air Conditioning? (UK Rules by Nation)

Planning permission for air conditioning in England, Wales, Scotland and Northern Ireland: when it's permitted development, the size and boundary rules, flats, listed buildings and noise.

By Max Tuleberg · Founder, Vento · Last updated 25 October 2026

Founder of Vento. Worked on the tools before building the software.

In England, air conditioning that can heat as well as cool is usually permitted development on a house — no planning application needed — as long as it meets the conditions below. Wales adopted similar rules on 1 June 2026. Scotland and Northern Ireland are stricter, cooling-only units need permission everywhere, and listed buildings always need consent.

The rules by nation

Permitted development for air-to-air heat pumps (air conditioning that heats), by UK nation, checked 24 October 2026
	England	Wales	Scotland	Northern Ireland
Air conditioning that also heats	Yes, since 29 May 2025	Yes, since 1 June 2026	Heating or hot water only — reversible units unclear	Must provide heat; cooling not addressed
Cooling-only unit	Needs permission	Needs permission	Needs permission	Needs permission
Boundary distance	None	None (3 m rule removed)	None	At least 1 m from a neighbouring dwelling's curtilage
Outdoor unit size (house)	Up to 1.5 m³	Up to 1.5 m³	No volume limit; max 1 m protrusion	No volume limit; max 3 m high
Units per house	2 if detached, otherwise 1	2 if detached, otherwise 1	1 per building	1
Blocks of flats	1 per block, up to 0.6 m³	1 per block, up to 1 m³	1 per building	Not covered
Noise standard	MCS 020 a) only	MCS 020 a) only	MCS 020 or equivalent	MCS 020 or equivalent
Listed buildings	Never permitted development	Never permitted development	Never permitted development	Not unless consent was granted

England in detail

Air source heat pumps — including reversible air-to-air units — are permitted development under Class G, as amended on 29 May 2025. The unit must not be used solely for cooling. The main conditions:

Outdoor unit (including any housing) no bigger than 1.5 m³ on a house, 0.6 m³ on a block of flats.
Up to two units on a detached house; one on a semi-detached or terraced house; one on a whole block of flats.
No boundary-distance rule any more — the old 1 m rule has gone.
Must pass the MCS 020 a) noise calculation. Since 28 May 2026 that is the only accepted standard.
Not on a pitched roof; on a flat roof, at least 1 m from the edge.
In a conservation area or World Heritage Site: not on a wall or roof facing a road, and not nearer the road than the house. Elsewhere, not on a road-facing wall above the ground floor.
Not within the curtilage of a listed building, or on a scheduled monument.
Sited to minimise its effect on appearance and neighbours, and removed when no longer needed.

Your council can remove these rights in a particular area with an Article 4 direction, so if you're in a conservation area it's worth checking with them first.

Wales

From 1 June 2026 Wales allows reversible units that aren't used solely for cooling, up to 1.5 m³ on a house and 1 m³ on a block of flats, two on a detached house and one otherwise. Wales previously had a 3 m boundary rule; that has been removed. Units must meet MCS 020(a).

Scotland

Scotland allows one air source heat pump per building, with no boundary-distance rule, but the pump may only be used for domestic heating or hot water. A reversible unit used for cooling is arguably outside the rules. The Scottish Government has consulted on allowing cooling, but no change has been made, so speak to your council before fitting air conditioning.

Northern Ireland

Northern Ireland allows one heat pump per house that provides heat, at least 1 m from the boundary with a neighbouring dwelling's curtilage, no more than 3 m high and not on a roof. The rules don't mention cooling, and they don't cover flats.

Flats and leasehold homes

Planning permission and your lease are separate. Even where a unit is permitted development, your lease may require the freeholder's consent to alterations. In England and Wales, where a lease requires consent for improvements, the law treats that consent as not to be unreasonably withheld — but the freeholder can still attach reasonable conditions.

Listed buildings

Permitted development never applies within the curtilage of a listed building. You will need listed building consent for works that affect its character, and possibly planning permission as well.

Building Regulations are separate

Even without planning permission, installing fixed air conditioning in a home is notifiable building work in England — usually handled by an installer registered with a competent person scheme. See Building Regulations for air conditioning.

Sources

Checked on 24 October 2026. Planning rules change — confirm with your council before you rely on them.

This guide is general information for UK installers, not legal or regulatory advice. Always check the current regulations and manufacturer instructions for your specific job.

Frequently asked questions

Do I need planning permission for air conditioning in England?

Usually not for a house, if the outdoor unit can heat as well as cool. Since 29 May 2025, reversible air-to-air heat pumps are permitted development in England, subject to conditions: an outdoor unit of no more than 1.5 m³ on a house, up to two units on a detached house and one on a semi or terrace, compliance with the MCS 020 a) noise calculation, and restrictions in conservation areas and on walls facing a road. A cooling-only unit needs a planning application, and listed buildings always need consent.

Do air conditioning units still have to be 1 metre from the boundary?

Not in England (the 1 m rule was removed on 29 May 2025) or Wales (which had a 3 m rule, removed on 1 June 2026). Northern Ireland still requires the unit to be at least 1 m from the boundary with another dwelling's curtilage.

Does air conditioning need planning permission in Scotland?

Scotland's permitted development rules allow one air source heat pump per building, but only for domestic heating or hot water. A reversible air-to-air unit used for cooling is arguably outside those rules, so check with your council before installing.

Can I put air conditioning on a flat?

In England, permitted development allows only one unit on a whole block of flats (up to 0.6 m³), and only where the building is entirely flats; in Wales one per block up to 1 m³. A second flat owner, or a block with shops, needs planning permission. Separately, your lease may require the freeholder's consent.