Portsmouth: 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 Portsmouth whatever the property, because on its own it only cools.

So the system you choose changes your planning path in Portsmouth, not just your comfort. The same box that both heats and cools opens the permitted-development route on a house; a unit that only cools does not. About 13% of Portsmouth's EPC-certified stock falls inside a conservation area, concentrated around Hilsea Lines, King Street, Stanley Street, Southsea; most homes sit outside one, but it is still worth checking the boundary before you commit to a wall-mounted unit.

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 Portsmouth flat will usually need both freeholder or managing-agent consent and planning permission.

Portsmouth sits in the middle nationally on conservation coverage, at around 13% of properties (including parts of Hilsea Lines, King Street and Stanley Street, Southsea). Whether permitted development is available for your outdoor unit genuinely depends on which part of the borough your home sits in, which is exactly what our checker resolves for your address.

No planning application mentioning cooling equipment has reached our record for Portsmouth yet. That is a gap in what we hold rather than a statement about demand in Portsmouth, which is why there is no local approval rate on this page.

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 Portsmouth property types we profile averages around 47 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 should put you off. Councils across Portsmouth approve outdoor units for homes exactly like this all the time. Roughly 13% of properties sit inside a conservation area, and it is still a genuine step rather than a rubber stamp. Being near a listed building - around 2.7% of homes here sit within 30 metres of one is not the same as being listed yourself, and public records can raise a conservation-area flag without resolving it. This stays indicative, not legal advice: confirm with your Local Planning Authority before you install.