Most installations do not need planning permission

In the vast majority of cases, installing a split system air conditioner at a domestic property falls under permitted development rights — meaning you do not need to apply for planning permission. This applies to both the indoor unit and the outdoor condenser unit, provided certain conditions are met.

When permitted development applies

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Permitted development rights for air conditioning at a domestic property generally apply when:

  • The outdoor unit is not installed on a wall or roof that faces a highway
  • The unit is not installed on a flat roof
  • There is only one outdoor unit on the property after installation
  • The unit is removed when no longer needed
  • The property is not in a designated area (conservation area, National Park, AONB)
  • The property is not a listed building

When planning permission is required

You will need to apply for planning permission — or may be refused outright — in the following circumstances:

  • The property is a listed building (any external changes require Listed Building Consent)
  • The property is in a conservation area and the unit would be visible from a public highway
  • The installation involves more than one outdoor unit and PD rights do not cover it
  • The property is a flat or maisonette in some cases — check with your local planning authority

Leasehold and flats

If you own a leasehold flat, you will almost certainly need permission from your freeholder or managing agent before installation, regardless of planning rules. Check your lease and contact your managing agent before booking any work.

Commercial properties

Commercial properties do not benefit from the same permitted development rights as domestic properties. You should check with your local planning authority before installing air conditioning on a commercial building, particularly if it is in a town centre or conservation area.

When in doubt, ask the engineer

A reputable air conditioning installer will be familiar with local planning rules and can advise whether your installation is likely to need permission. Get free quotes from vetted local engineers who can survey your property and guide you through the process.