Planning Permission for Air Conditioning in a Flat: UK Guide
If you live in a flat and want air conditioning, the short answer is that the outdoor unit usually does need planning permission, and you will almost certainly need your freeholder's consent too. It is not as daunting as it sounds, but skipping these steps can lead to enforcement notices or problems when you sell. Here is how it actually works for flats in Fulham and across London.
Why flats are treated differently from houses
Most home improvements are covered by permitted development rights, which let you carry out certain works without a planning application. The catch is that flats and maisonettes do not benefit from most of these rights, and the rights that do exist for heating and cooling equipment are narrower than people expect.
There is a permitted development allowance for air source heat pumps, and since changes to the rules it can apply to blocks of flats in some circumstances. However, a standard split system air conditioner installed purely for cooling is not a heat pump in planning terms, so it generally falls outside that allowance. In practice, fixing a condenser unit to the outside wall of a flat, on a balcony, or on a shared roof normally requires planning permission from the local council, which in Fulham means the London Borough of Hammersmith and Fulham.
The two consents you actually need
Planning permission is only half the picture. Because your flat is almost certainly leasehold, the external walls, roof and often the balconies belong to the freeholder, not to you. Drilling through the wall and mounting a unit on it means altering their property, so you need written consent, usually called a licence to alter or licence for alterations.
Managing agents will typically want to see drawings showing the unit's position, the manufacturer's noise data, and confirmation that a qualified F-Gas registered engineer will do the work. Some blocks refuse external units outright, so it is worth checking your lease and asking the managing agent before you spend money on surveys or applications.
- Planning permission from Hammersmith and Fulham council for the external unit
- Freeholder or managing agent consent, usually as a licence to alter
- F-Gas certified installation, which is a legal requirement for any split system
What the council will look at
A householder or full planning application currently costs a few hundred pounds in fees, and the council aims to decide within eight weeks. The main things officers assess are noise, visual impact and heritage. Modern condensers are quiet, often around 45 to 55 decibels at one metre, but you will usually need an acoustic report showing the unit will not disturb neighbouring bedrooms, particularly at night.
Location matters a great deal in this part of London. Large areas of Fulham sit within conservation areas, and if your building is listed you will need listed building consent as well. Units visible from the street are much harder to get approved than those tucked on a rear wall, in a lightwell or screened on a flat roof. A well prepared application with accurate drawings and noise data stands a far better chance than a bare form.
What happens if you install without permission
Installing first and hoping nobody notices is a genuine risk in a flat. Neighbours can and do report units, and the council can serve an enforcement notice requiring removal at your own cost. Your freeholder can also demand removal under the lease, and an unauthorised unit will show up when a buyer's solicitor raises enquiries, which can stall or sink a sale.
If a unit is already in place, retrospective planning permission is sometimes possible, and we can advise on whether an existing installation is likely to be acceptable or whether relocating or replacing it with a quieter model would help.
Options if permission is refused or not practical
If your freeholder says no or the planning constraints are too tight, you are not out of options. Systems with a concealed condenser, such as those housed in a lightwell or internal plant space with ducted air paths, can sometimes work where a wall mounted unit cannot. Portable units avoid the issue entirely but are noisier and far less efficient, so we treat them as a last resort rather than a solution.
Every block is different, so the sensible first step is a site survey. A good installer will tell you honestly whether your flat is a realistic candidate before you commit to application fees or freeholder legal costs, which together often run to several hundred pounds or more.
Common questions, plainly answered
Do I need planning permission for a portable air conditioner in my flat?
No. Portable units have no fixed external parts, so planning permission and freeholder consent for alterations do not apply. The trade off is higher running costs, more noise indoors and weaker cooling than a fixed split system.
How long does the whole process take?
Allow roughly two to four months from survey to installation. Planning decisions target eight weeks, and freeholder consent can run alongside but sometimes takes longer, especially if the managing agent involves their surveyor or solicitor.
Does the heat pump permitted development rule cover my air conditioning unit?
Usually not. The allowance applies to air source heat pumps used for heating, or heating and cooling, and comes with strict conditions on siting and noise. A cooling only split system does not qualify, so in a flat you should assume a planning application is needed.