Do I need planning permission for AC in the UK?
The answer depends almost entirely on your property type. Most houses don't need it. Flats, listed buildings, and conservation areas are different. Here's the complete picture — including what to do if you do need permission.
The Quick Answer by Property Type
| Property type | Planning position |
|---|---|
| Detached and semi-detached houses | Usually no permission needed — permitted development |
| Terraced houses | Usually no permission needed — not on front elevation |
| Flats and apartments | Planning permission required for external units |
| Listed buildings | Listed building consent required regardless of property type |
| Conservation areas | Additional restrictions — check with local authority |
| Leasehold properties | Check your lease — freeholder consent may be required |
Permitted development rules for houses
In England, most residential AC installations on houses are covered by permitted development rights — meaning you don’t need to apply for planning permission. However, the installation must meet all of the following conditions:
- Unit volume must not exceed 0.6m³. Standard residential units are well within this limit.
- Not on a wall or roof facing a highway. Rear and side walls are fine in most cases.
- Not on a flat roof. A full planning application would be required.
- Noise limit at neighbors’ window. From May 2026, new installations must not exceed 37dB (MCS 020 standard).
- Only one unit per property under permitted development. A second unit would require planning permission.
Flats and apartments
Permitted development rights do not apply to flats or maisonettes. If you live in a flat and want to install AC, you will typically need:
Planning permission from your local authority
For the external condenser unit. This involves submitting a planning application, which costs £206 in England (2026). Most straightforward residential applications are decided within 8 weeks.
Freeholder or management company consent
Even if planning is granted, your lease almost certainly requires written consent from the freeholder or managing agent before any external alterations. Check your lease before proceeding. The good news: many flat installations are approved, particularly where the unit can be positioned on a rear or internal courtyard elevation. Your Temlo installer will advise on the best placement.
Listed buildings
If your property is listed — Grade I, Grade II*, or Grade II — any external alteration requires listed building consent from your local planning authority, in addition to any planning permission that might be required. This applies regardless of whether you own a house or a flat.
Your installer will advise on the best approach for your specific property. For listed buildings, we recommend speaking to your local conservation officer before submitting any application — many will indicate likely approval informally before you commit to a formal application.
Conservation areas
Properties in conservation areas have additional restrictions beyond standard permitted development. Key rules:
- Units on any wall facing a road or public space require planning permission in a conservation area, regardless of size.
- If the unit is on a rear wall not visible from the street, standard permitted development rules often still apply. Check with your local authority to confirm.
West Sussex has a number of conservation areas — particularly in Chichester and Arundel. London has hundreds. If you’re unsure whether your property is in one, your installer will check during the site visit, or you can search your local authority’s planning portal.
How to apply if you need permission
| System | Timeframe | Cost |
|---|---|---|
| Single Split System | 1 | £206 application fee |
| Twin Split (multi-room) | 2 | Included |
| Triple Split (multi-room) | 3 | — |
| Quad Split (multi-room) | 4 | — |
Alternatively, a Lawful Development Certificate (£103) provides written confirmation from your local authority that your installation is permitted development — useful if you want certainty before proceeding, or if you’re planning to sell and want to document compliance.
What your Temlo installer will advise
Every Temlo installer assesses planning requirements as part of the site visit. They’ll confirm whether your installation is permitted development, advise on the best unit placement to meet planning conditions or maximise approval chances, and guide you through any application process if needed. You don’t need to resolve the planning question before getting an estimate. Start the process and your installer will take it from there.
Get a free estimate at Temlohome.com — your installer will advise on planning during the site visit.
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