Can you put air conditioning in a flat? The question lands in search engines every warm June, usually from someone on the top floor watching the thermometer climb. The honest answer is that you usually can, but not on your own say-so, and the paperwork matters more than the plumbing.
Why your freeholder gets a vote
A split system needs an outdoor unit, and in most flats the external walls, the roof and often the balcony structure belong to the freeholder, not to you. Fixing a condenser to any of them without consent is a lease breach, and freeholders have made people remove perfectly good installations for exactly that. So the first document to read is your lease, and the first letter to write goes to the freeholder or managing agent, describing what you want to fit and where. Some agents have a standard licence for alterations ready to go. Others take months, which is another argument for starting well before summer.
Planning permission is not the formality it is for houses
Homeowners in houses often fit air conditioning under permitted development, subject to conditions. Flats and maisonettes do not get those rights, so an outdoor unit on a flat generally needs planning permission as well as freeholder consent. Councils mostly care about two things: how the unit looks on the building, and how much noise it makes for the neighbours. A condenser tucked on a rear balcony or a flat roof, out of sight of the street, has a far easier ride than one bolted to the front elevation.
Where the outdoor unit can live
Installers who work on flats regularly have a short list of workable spots: a balcony with airflow around the unit, a flat roof with safe access, or an external wall facing a courtyard rather than a street. What they will steer you away from is anything that boxes the condenser in, because these units need to breathe, and anything directly under a neighbour's bedroom window. If you are a tenant rather than a leaseholder, add the landlord's written permission to the pile before anyone drills.
Getting it done without the drama
None of this should put you off. Flats get air conditioning fitted every week, and the jobs that go wrong are almost always the ones where the drilling happened before the permissions did. An installer who regularly works on apartment blocks will ask about your lease at the survey and will supply the noise data the council or the freeholder wants to see.
Of the 996 air conditioning companies listed on this site, a good number handle flat and apartment work as a matter of routine, and their listings say so. Look through companies covering your postcode, or set out your situation and let experienced firms respond. Before any of that, do the free step first: dig out your lease this week and find the clause on alterations. Everything else follows from what it says.
