Air conditioning
planning permission

The eight conditions, in full

These come from the Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 14, Class G. If your installation meets every one of them, you do not need a planning application. Break one and you do.

This is the position in England. Scotland, Wales and Northern Ireland have their own equivalent rules. Class G covers houses, not flats.

When you definitely do need permission

A householder planning application in England costs 258 pounds and is normally determined in eight weeks. Listed building consent has no fee but takes longer.

The noise condition, which is the one that gets missed

MCS 020 is the standard the permitted development rules point at, and it is not a rule about how loud the unit is. It is a rule about the sound level at the nearest habitable room window of a neighbouring property, with a limit of 42 decibels.

That matters because it means the answer depends on your neighbour's window, not your unit. The same machine passes easily at the end of a long garden and fails on a narrow terrace where the outdoor unit would sit four metres from next door's bedroom. Distance, direction of discharge and any solid barrier between the two do most of the work.

We assess this on the survey rather than assuming it, because a unit that has to move after a complaint costs far more than a unit positioned correctly first time.

Conservation areas and Article 4

Being in a conservation area does not remove your permitted development rights. It adds one restriction: the unit cannot be on a wall or roof slope fronting a highway. For a mid-terrace that usually pushes the unit to the rear, which is where it was going anyway.

An Article 4 direction is different and more serious. It is a formal direction by the council that removes specified permitted development rights in a defined area, and where one applies you need planning permission for work that would otherwise be automatic. Article 4 directions are common in London and are mapped street by street on each council's own website.

The boroughs we cover

The proportion of a borough sitting inside a conservation area is the single best predictor of whether your street will be a straightforward job or a conversation with the council. This is where each borough sits.

We check the specific position for your address, including any Article 4 direction and whether your street is inside a conservation area boundary, before we quote. We do not publish a council's position here until we have read that council's own guidance, because a wrong planning answer is worse than no answer.

What we do about it

1. Check your address against the conservation area map, the Article 4 map and the listed building register before we quote.
2. Position the unit to stay inside permitted development wherever it is possible, because that is faster and cheaper for you than any application.
3. Assess the noise position against the nearest neighbouring window under MCS 020.
4. Tell you plainly if an application is needed, what it costs and how long it takes, before you commit to anything.