Canterbury: air conditioning planning permission

Since 2025-05-29, England's permitted-development rules let a house fit an air-to-air heat pump - which heats as well as cools - without a planning application in many cases, within set size, siting and noise limits. A cooling-only air conditioning unit does not get that route and needs a full planning application in Canterbury whatever the property, because on its own it only cools.

In Canterbury, the system you choose is a planning decision as much as a comfort one. An air-to-air heat pump on a house qualifies for permitted development because it does both jobs; a unit that only cools is excluded from that route entirely. With around 30% of Canterbury's EPC-certified stock inside a conservation area (NUNNERY FIELDS (Canterbury Conservation Area) registered 12.11.1998, 1937 KENT AND CANTERBURY HOSPITAL (Canterbury Conservation Area) Reg 12/11/1998, OLD DOVER ROAD, OATEN HILL AND ST. LAWRENCE. Canterbury Cons Area. reg 12/11/1998 among them), confirming the exact boundary before you site an outdoor unit is the single most valuable planning step to take here.

Flats are the sharpest exception here as everywhere in England: the permitted-development right for an outdoor unit sits with the house, not the flat, so a Canterbury flat will usually need both freeholder or managing-agent consent and planning permission.

Conservation-area coverage runs high in Canterbury - about 30.2% of properties sit inside one, including NUNNERY FIELDS (Canterbury Conservation Area) registered 12.11.1998, 1937 KENT AND CANTERBURY HOSPITAL (Canterbury Conservation Area) Reg 12/11/1998 and OLD DOVER ROAD, OATEN HILL AND ST. LAWRENCE. Canterbury Cons Area. reg 12/11/1998. That tightens or removes the usual permitted-development right for a house, so an outdoor unit facing the street will typically need Canterbury Council to approve planning permission first.

Across all development types, Canterbury has decided 55 planning applications mentioning air conditioning or other cooling plant - 17 of them householder applications - and approved 96.4% of the 55.

Put as counts: 53 went through, 2 did not.

There is no householder-only percentage here, deliberately. 17 decided householder applications is not enough for a rate to mean anything, so the count is all we will state.

These are applications whose own description names cooling equipment. An application that installed the same kit but described it as external plant is not in the Canterbury count.

A different question, kept separate on purpose: 100% of the 37 applications mentioning an air-source heat pump that Canterbury has decided were approved. Air-source usually means a heating scheme, not a cooling one, and an application can sit in both sets, so the two figures are never summed or averaged.

What actually gets refused, and what councils attach when they approve, is a national picture rather than a local one at the volume of officer reasoning currently published. We set both out with their sample sizes: why cooling applications get refused and the conditions councils attach.

You can also compare what each council decides, where enough decisions exist to publish a figure.

Ambient daytime noise across the Canterbury property types we profile averages around 41 dB, and that background level matters as much as the machine's own rating: the same unit that vanishes against a main road can be the loudest thing in a quiet back garden.

Siting is the lever. Keeping the outdoor unit away from a neighbour's window and back from the boundary is what most often turns a marginal case into an approved one.

None of this is a dealbreaker: councils in Canterbury approve outdoor units for homes like these all the time. Around 30.2% of local properties sit inside a conservation area, so it is a step to plan for rather than a formality. Being close to a listed building - around 7.9% of homes here sit within 30 metres of one is not the same as your home being listed, and public data can flag conservation status without settling it. This is indicative guidance, not legal advice: confirm the final position with your Local Planning Authority before you install.