Do you need planning permission for air conditioning in London?

One of the most common questions we hear from London homeowners is whether air conditioning needs planning permission. The short answer is: usually no, but there are important exceptions depending on where you live and what type of building you have.

Permitted development for domestic AC

For most houses and bungalows, installing a standard split-system air conditioner counts as permitted development. That means you do not need to apply for planning permission, provided the outdoor unit is placed sensibly and does not protrude significantly beyond the property boundary.

• The outdoor unit must be sited at ground level or on a flat roof in most cases
• It should not be positioned on a wall facing a highway if it projects more than allowed
• It must be removed if the system is no longer needed, unless it becomes part of a longer-term permitted design

When planning permission is required

Planning permission becomes necessary when the installation goes beyond standard permitted development rights. This is especially common in London, where conservation areas, listed buildings and leasehold flats introduce extra layers of control.

1. Listed buildings: you will need listed building consent for any external unit or visible pipework
2. Conservation areas and Areas of Outstanding Natural Beauty: stricter placement rules apply
3. Flats and maisonettes: permitted development rights are more limited than for houses
4. Properties with Article 4 directions: planning permission may be needed for changes not normally controlled

Building regulations and noise

Even when planning permission is not needed, the installation must still comply with building regulations. Electrical work must be certified, and the outdoor unit must be fixed safely so it cannot fall or vibrate excessively.

Noise is another key consideration. Local councils can investigate complaints under nuisance law, and some newer units are far quieter than older models. We specify low-noise units and position them away from bedroom windows where possible.

Party wall and neighbour considerations

If you live in a terraced or semi-detached house and the outdoor unit is mounted on a shared wall, you may need a party wall agreement. Even when not legally required, it is good practice to discuss the placement with neighbours before work begins.

“A quick five-minute chat with a neighbour can prevent a three-month dispute. We always try to keep units off shared boundaries unless there is no practical alternative.”

How we help with compliance

During our free site survey, we check whether your property is listed, in a conservation area, affected by Article 4 directions, or likely to need party wall consultation. If planning permission or listed building consent is required, we can provide the technical drawings and specifications your architect or council will need.