Do I need planning permission for air conditioning?

Use the planning checker

The planning checker gives you a starting answer in up to four quick questions. It covers homes in England.

Units that cool without heating

Units that cool without heating usually need planning permission, because the rights that cover heat pumps leave them out. Since 29 May 2025 the law has said a heat pump can’t be used solely for cooling under these rights.

The government adds a caveat. It says that in most cases a small home needs no permission, if the unit wouldn’t materially change how the building looks from outside. It also says there’s no blanket rule, and that people should ask their council.

Most split units heat as well as cool, so check the data sheet before you decide. Air-to-air heat pumps explained.

Sources: the planning order, the Planning Portal and the housing ministry (June 2026).

Heat pumps and permitted development

Permitted development means you can do the work without a planning application, if it stays within set limits. An air conditioner that heats as well can count as an air source heat pump. The Planning Portal says these rights cover units that do both.

On a house in England, the main limits are:

• one unit on a terraced or semi-detached house, two on a detached house
• an outdoor unit of 1.5 cubic metres at most, with any housing
• not on a pitched roof, and at least 1 metre from the edge of a flat roof
• not on a wall facing a road, above the ground floor
• a noise calculation that meets MCS 020(a)
• sited to limit its effect on how the building looks and on the area

The unit must also come down once it’s no longer needed. Your council may have removed these rights with an Article 4 direction, which is most common in conservation areas. The best spots for an outdoor unit.

Sources: the planning order and the Planning Portal.

Flats and maisonettes

Flats and maisonettes don’t get the rights that houses have, so an outdoor unit usually needs planning permission. A block of flats gets one heat pump at most, with an outdoor unit up to 0.6 cubic metres.

That allowance covers the whole block, so it rarely helps one flat owner. Your freeholder has a say as well. What to agree in a flat.

Source: the planning order’s definitions.

Listed buildings and conservation areas

Air conditioning on a listed building gets no permitted development rights, so expect to need planning permission and listed building consent. The same applies within the building’s grounds.

Air conditioning in a conservation area has tighter limits. A heat pump can’t go on a wall or roof facing a road, or nearer the road than the house. World Heritage Sites have the same limits.

The Planning Portal’s own advice is stricter, and says permission will be required in a conservation area. So ask your council before you buy. Many councils also publish guidance on where a unit should sit.

Sources: the planning order and the Planning Portal.

Noise and the outdoor unit

Noise matters to planning because a heat pump must pass the MCS 020(a) sound calculation to count as permitted development. If you apply for permission, your council may ask about noise too.

Position does most of the work, so keep the unit away from neighbours’ windows. How loud air con is.

How to apply

A planning application goes to your council, in five steps:

1. Ask your council’s planning team whether you need to apply.
2. Prepare plans showing where each part goes, with the unit’s details.
3. Apply through the Planning Portal or your council’s website, and pay the fee.
4. Wait for the decision, which should come within 8 weeks.
5. Start the work once you have the decision in writing.

A lawful development certificate is worth knowing about. It’s the council’s formal confirmation that the work would be lawful, and anyone can apply for one.

Sources: GOV.UK on decisions and GOV.UK on certificates.

What an application costs

An application usually adds two costs to the fitting:

• The council’s fee: £548 for a householder application, from 1 April 2026.
• A noise report: £600 to £1,400, in one London firm’s 2026 guide. That’s their estimate, not our price.

Freeholders are harder to predict, because nobody publishes how often they say yes. Consent often comes as a licence to alter, which one London practice puts at £400 to £2,000. That’s their estimate, not our price.

Sources: the Planning Portal’s fee guide, MMES Specialist Consulting and Architecture for London.

Scotland, Wales and Northern Ireland

Scotland, Wales and Northern Ireland each have their own rules, so the checker doesn’t apply there:

• Wales: rules updated on 1 June 2026 let most homes take a heat pump that heats, or heats and cools, within limits. A unit designed for cooling alone isn’t covered.
• Scotland: the rules allow one heat pump on a dwelling, used for domestic heating or hot water. A unit bought for cooling may fall outside that, so ask your council.
• Northern Ireland: since 4 July 2023 a domestic heat pump needs no permission if it meets set conditions. Those include 1 metre from a neighbour’s boundary, and a noise standard.

Sources: the Welsh Government, the Scottish order and the Department for Infrastructure.