Do I need planning permission for air conditioning in Westminster?

The short answer

Planning permission can be needed in Westminster. Much of the borough is covered by conservation areas, where Class G does not permit a condenser unit on a wall or roof that fronts a highway, or nearer to a bounding highway than the nearest part of the building. Listed status, Article 4 directions and the other Class G conditions can also change the answer.

A condenser unit is the outdoor half of the system — a box about the size of a suitcase. Where it goes decides whether you need permission.

Permitted development rules

For houses, an air-source heat pump can be permitted development if every Class G limit and condition is met, including MCS 020a compliance, the outdoor-unit size limit and the restrictions on street-facing walls. There is no standalone one-metre property-edge condition in the current national guidance. That's called permitted development — work you can do without asking the council.

Class G can also apply to a block of flats if every national limit and condition is met. In Westminster, check the exact address with the council and obtain any required freeholder consent before installation.

Flats and conservation areas

Conservation areas cover much of central Westminster — including Marylebone, Mayfair, Soho and Pimlico. A unit visible from the street is not automatically prohibited, but the national permitted-development route has specific highway-facing restrictions in conservation areas and Westminster may have further controls.

Your installer will look at where the unit can physically go, then advise whether a full application or a lawful development certificate is right.

How to apply in Westminster

Applications go through Westminster City Council's planning portal. Your MCS certified installer usually handles the drawings and submission, or points you to a planning consultant if the case is unusual.

What installers handle for you

An MCS certified installer applies for the grant on your behalf. Ask whether they can help with any freeholder process or planning paperwork; responsibility and service scope vary by installer.