The short answer
Tenants usually need the landlord's written permission before fitting fixed air conditioning, and a flat's landlord may need the freeholder's consent too. Portable units usually don't need permission, as long as nothing is drilled or altered.
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A fixed system alters the building, so in a rented home the owner of the building has a say, and the arrangements need to cover the years the system is in use, not just the day it goes in. Tenancy law differs between England, Wales, Scotland and Northern Ireland, and so do individual agreements, so what follows is general.
If you rent your home
Tenancy agreements usually don't allow alterations without the landlord's consent. A split system involves holes through an outside wall, brackets or a stand for the outdoor unit and often a new electrical circuit, so it counts as an alteration.
The clearest approach is to ask your landlord in writing, with details of what would be fitted and where, and to get the answer in writing too. This applies equally to council and housing association homes, where the landlord usually has its own process for requests.
A few things can affect the answer:
- Flats. Your landlord may be a leaseholder who needs the freeholder's consent as well. Flats and leasehold homes explains how that works.
- Planning. A landlord's permission doesn't replace planning rules, which still apply to the outdoor unit.
- The building itself. Listed buildings and some shared buildings have extra restrictions.
Fitting a system without permission can breach the tenancy agreement, and the landlord could ask for it to be removed and any damage put right.
What to agree in writing
If a landlord agrees, the details matter as much as the yes. A short written agreement can settle the questions that otherwise come up years later.
| Question | Why it matters |
|---|---|
| Who owns the system | Whether it stays when you leave |
| Who arranges servicing | Often yearly; some warranties depend on it |
| Who deals with faults | Repairs need an engineer, and access |
| What happens when you move out | Removal means recovering the refrigerant |
| Making good | Holes and fixings left after removal |
A split system can't simply be unbolted and taken to the next home. Disconnecting it means handling the refrigerant, which only a qualified engineer can do, and when a system is removed for good the refrigerant is recovered, as covered in Removing and disposing of an old system.
Portable units and other options
A portable air conditioner plugs into a socket and vents warm air through a hose, usually out of a window. Because nothing is fixed to the building, it usually doesn't need the landlord's permission. A window kit that's screwed or drilled into the frame is different, as that alters the window.
Portable units have their own trade-offs, including noise in the room and the gap the hose needs. There are also ways to keep rooms cooler without any air conditioning, such as shading windows from the sun and ventilating at night, covered in Keeping cool without air conditioning.
If you're a landlord
Fitting air conditioning to a rented home involves the same rules as any other home, plus a few extra points.
- Permissions. Planning rules apply as normal. If you own a leasehold flat, the freeholder's consent is usually needed.
- Responsibility. Landlords have legal duties to keep certain installations in repair, and these can extend to a system that heats the home. Tenancy law differs across the UK, so the position for a particular property is one to check.
- Instructions. Tenants need to know how to use the system, and who cleans the filters, which usually needs doing every few weeks while it's in regular use.
- Access. Servicing and repairs need access to the indoor and outdoor units, which tenancy agreements usually cover.
- Paperwork. Keep the electrical certificate, commissioning records and noise calculation with the property's other documents.
A system installed by a landlord generally becomes part of the property. If a tenant fitted a system with permission, the written agreement made at the time is the clearest guide to whether it stays or goes when the tenancy ends.
Related guides
- Flats and leasehold homesIn a flat or leasehold home, fitting air conditioning usually needs written consent from the freeholder under the lease, and the planning rules for flats differ from those for houses. Freeholder consent and planning are separate questions.
- Portable air conditionersA portable air conditioner is a self-contained unit on wheels that cools a room and sends the heat outside through a hose, usually out of a window. It needs no professional installation, but it is noisier and less effective than a fixed split system.
- Keeping cool without air conditioningKeep the sun off your windows during the day, open up when the air outside is cooler than inside, usually from late evening to early morning, and cut the heat produced indoors. Fans make you feel cooler, though they don't cool the room.
- Removing and disposing of an old systemAn old split system has to be taken out by a qualified engineer, who recovers the refrigerant before anything is disconnected. The units then go for recycling as electrical waste, and the holes and fixings left behind need making good.