Many guides say air conditioning never needs planning permission. That isn’t quite right. In England, the permitted development rights that let you fit an outdoor unit without applying are written for heat pumps, and they come with conditions. A unit that only cools isn’t covered by them at all.
This guide follows the rules on the Planning Portal for England. Wales, Scotland and Northern Ireland have their own rules. It’s general information, not legal advice: your local planning authority has the final word.
Air conditioning and heat pumps
Most modern split air conditioning can heat as well as cool. In that form it’s an air-to-air heat pump. The Energy Saving Trust says “air-to-air heat pumps are sometimes referred to as air conditioning”.
This matters for planning. Since 2025, permitted development for air source heat pumps on houses in England covers air-to-air heat pumps as well as air-to-water. So a reversible system used for heating can fall under it, if it meets the conditions below. A cooling-only unit can’t, because one of the conditions is that the unit is not used solely for cooling.
The conditions for a house
According to the Planning Portal, an air source heat pump on a house can be permitted development if:
- the outdoor unit, including its housing, is no more than 1.5 m³;
- the installation complies with the MCS 020(a) planning standard, which includes a noise check. From 28 May 2026, MCS 020a is the only permitted scheme;
- it is not used solely for cooling;
- it isn’t within the curtilage of a listed building or on a scheduled monument;
- it isn’t on a pitched roof, and on a flat roof every part is at least 1 m from the edge;
- outside conservation areas, it isn’t on a wall above ground floor that fronts a highway;
- only one is fitted on a house that isn’t detached; a detached house may have two.
It must also be sited, as far as practicable, to keep its effect on the building’s appearance and the area’s amenity to a minimum, and removed once it’s no longer needed.
Cooling-only units
If the system only cools, the heat pump rights don’t apply. Fixing an outdoor unit to a building can count as development, so check with your council before you go ahead. Many councils offer pre-application advice. In practice a small unit on a rear wall is less likely to raise concerns than one on the front of the house, but that’s the council’s decision, not ours or yours.
If you’re choosing between models, a reversible system you’ll use for heating keeps the permitted development route open. We can explain the difference on the survey.
Listed buildings
Permitted development doesn’t apply within the curtilage of a listed building. On top of planning, listed building consent is a separate matter. It covers works that affect the building’s character, which can include drilling through historic walls, fixing units and running pipework inside.
Careful positioning helps: a rear courtyard, a later extension or a flat roof out of view, with fixings and pipe routes chosen to do as little harm to historic fabric as possible. Talk to the council’s conservation officer early. Our listed building guide and listed buildings page cover the practical side.
Want it done properly? AirCon Doctor installs, repairs and services air conditioning and heat pumps across London and the South East, from our base in East Grinstead. We’re an F-Gas certified company and NICEIC approved. Get a fixed-price quote.
Conservation areas and World Heritage Sites
Heat pump permitted development can still apply in a conservation area or World Heritage Site, but the unit must not be on a wall or roof that fronts a highway, or nearer to a highway than any part of the building. That usually means the back or a side wall that doesn’t face the road.
Flats and leasehold properties
For a block made up wholly of flats, the Planning Portal sets tighter limits: the outdoor unit must be no more than 0.6 m³, and only the first installation is permitted. A block that also has commercial premises doesn’t qualify. Flats in converted houses or mixed-use buildings are worth checking with the council.
Planning is only half of it. Most leases control alterations to the outside of the building, and the landlord or managing agent will want to agree where the outdoor unit and pipes go. Ask before work starts. Our guide to leasehold consent explains what to send them, and the flats guide covers the technical choices.
Article 4 directions and planning conditions
Councils can remove permitted development rights in a particular area with an Article 4 direction. Rights can also be removed by a condition on the original planning permission for the house, which is common on newer estates. If either applies, you need to apply for planning permission even if the unit meets every other rule. Your council’s website, or a quick email to its planning team, will tell you.
Businesses and commercial buildings
The house and flat rules above don’t cover shops, offices, restaurants or other commercial buildings. External plant on a commercial building, especially on a roof or a street-facing wall, often needs planning permission, and the council may ask about noise. Check before you order equipment. Our commercial air conditioning page explains how we plan those jobs.
How we handle planning on a survey
On every survey we look at where the outdoor unit can go and ask about the property: listed status, conservation area, leasehold, previous planning conditions. If we think consent may be needed, we tell you before you commit, and we can suggest positions that are more likely to be acceptable. We never assume permission on your behalf. See our guide to outdoor unit positions, or get in touch.
Quick answers
Do I need planning permission for air conditioning on my house?
Not always. A reversible unit used for heating can be permitted development as an air source heat pump if it meets the conditions, including MCS 020a and the 1.5 m³ size limit. A cooling-only unit isn’t covered, so check with your council.
Can I put an air conditioning unit on the front of my house?
Outside conservation areas, not on a wall above ground floor that fronts a highway. In conservation areas, not on a wall or roof fronting a highway at all.
Do listed buildings need consent for air conditioning?
Permitted development doesn’t apply within the curtilage of a listed building, and listed building consent is a separate requirement. Speak to the conservation officer first.
What about flats?
Blocks made up wholly of flats have tighter limits (0.6 m³, one installation), and your lease will almost always need the landlord’s consent.
What is an Article 4 direction?
A council order that removes permitted development rights in an area, so you need planning permission even if the unit meets the normal rules.
Related services
- Air conditioning installation
- Air-to-air heat pumps
- Air conditioning in listed buildings
- Domestic air conditioning
More advice
- Where to Put an Air Conditioning Outdoor Unit
- Air Conditioning in a Leasehold Flat: Getting Consent
- Air Conditioning Installation in a Listed Building: Complete Guide
- Air Conditioning and Building Regulations: What You Need to Know
- Air Conditioning Noise: How Quiet Are Modern Systems?
- All advice
This guide is general information, checked against the sources linked on 30 October 2026. It isn’t legal, tax or financial advice. Rules, grants and product ranges change, so check the current position before you rely on it.