Air Conditioning When You Rent: What You Can Do Without Asking

Renters have fewer options than owners and get less coverage. Here’s what’s actually available to you.

What you can do without asking

All of this is removable and leaves the property as you found it:

• A portable air conditioner vented through an opening window. Nothing is fixed, nothing is altered, and it comes with you when you move.
• Fans of any kind.
• A dehumidifier, if the real problem is clamminess rather than temperature.
• Blinds and curtains you hang from existing fittings, or that clip into the window recess without fixings.
• Removable solar film on the glass — the static-cling type rather than adhesive.
• Draught excluders, door brushes and removable window seals.
• A cut foam-board or acrylic panel in an opening casement to vent the hose, friction-fitted with foam tape rather than screwed.

Check your agreement for one thing: clauses about appliances, particularly where energy bills are included in your rent. Some agreements have fair-usage terms, and a high-consumption appliance is exactly what those are written for.

What needs written permission

• Drilling anything — a wall vent, brackets, fixings for external shading
• A fixed split system of any kind
• Anything attached to the outside of the building
• Adhesive solar film, which can damage glazing or be difficult to remove
• Replacing or modifying window furniture

Get it in writing. A verbal yes from a letting agent is worth very little when the property changes hands or the agent moves on, and deposit disputes turn on evidence.

On planning permission — what we can and can’t tell you

An earlier version of this article stated that most domestic air conditioning installations fall under permitted development. We’ve removed that, because we couldn’t verify it to a standard we’re comfortable publishing.

What we found when we checked: the published sources — mostly installer websites — contradict each other on the size thresholds for an outdoor unit, and none of them was the legislation itself. Repeating a figure we can’t stand behind, on a page where getting it wrong has consequences, isn’t worth doing.

What all sources do agree on, and what’s worth knowing:

• Portable units vented through an opening window need no permission at all — nothing is installed or altered. This is the route almost every renter takes.
• Listed buildings have no permitted development rights for this, and unauthorised work is a criminal offence rather than a planning breach.
• Conservation areas carry an extra condition — an outdoor unit must not go on a wall or roof fronting a highway.
• An Article 4 Direction can remove permitted development rights entirely in a defined area.
• Flats are treated more restrictively than houses.
• Noise conditions apply, and a neighbour can complain to the council regardless of planning status.

For the current thresholds, check the Planning Portal or ask your local planning authority. Both are free, and a pre-application enquiry gives you something in writing.

Practically, as a tenant this is mostly your landlord’s problem rather than yours — you shouldn’t be commissioning a fixed installation on someone else’s building. Our installation law guide and heritage guide cover the wider picture.

Setting up so it leaves no trace

The skill that matters for renters.

Venting

The supplied slider kit is designed for sash and sliding windows. UK rentals are full of casement windows it won’t fit.

A cut panel is the reliable answer. Measure the opening casement, cut foam board or acrylic to fit the aperture exactly, cut a hole for the hose coupling, and seal the edges with foam tape. Friction-fit it — don’t screw or glue anything.

Keep the panel when you move; it’ll fit nothing else, but it proves you didn’t alter the window. Our seal kits guide covers the options, and our bay window guide covers making a panel properly.

Sealing

Foam tape and draught strip rather than anything adhesive that marks paintwork. Test a small area first — some tapes lift emulsion when removed, and that’s a deposit deduction.

Protecting the floor

These units produce water and weigh 25–35kg. A slow drip into carpet goes unnoticed until it stains and smells, and castor dents in carpet are a common end-of-tenancy argument.

Put it on a rigid board or an appliance drip tray. It levels the unit, spreads the load, and contains any leak. Our carpet guide covers this, including why a folded towel underneath is the wrong solution.

Electrics

Security

A window held open by a panel is a weak point, particularly on a ground floor or in a shared building.

• Use a rigid panel rather than foam where the window is accessible from outside
• Consider a window restrictor that still lets the casement close onto the panel
• Don’t leave it set up while the property is empty for any length of time
• Check your contents insurance — an insecure window can affect a claim

Our home security guide covers the general principles.

Asking your landlord for help

Worth doing, and more often successful than tenants expect — particularly where the property has a specific problem rather than just being hot in a heatwave.

What tends to work:

• Put it in writing, politely, describing the problem factually. Temperature readings over several days are more persuasive than “it’s unbearable”.
• Frame it as a property issue if it is one. A window that won’t open, a broken extractor, a loft with no insulation, a restricted-opening mechanism that’s jammed — these are maintenance matters, not comfort preferences.
• Offer to share the cost of something that improves the property permanently, like external shading or loft insulation. Landlords are more receptive to things that outlast your tenancy.
• Ask for permission rather than forgiveness on anything permanent.

The picks

The free measures matter more when you rent

You have less control over the building, so what you can do in your own space counts for more:

• Shade sun-facing windows from mid-morning, before the room heats. The highest-value free action, and closing curtains at 6pm achieves very little by comparison.
• Purge ventilate once outside is genuinely cooler than inside, then shut up in the morning — our timing guide covers judging it.
• Close internal doors to the room you’re cooling.
• Switch off electronics. A desktop and monitors generate real heat in a small bedroom.
• Sleep in the coolest room, even if it isn’t the usual bedroom — ground floor and north-facing beats upstairs.

When you move out

1. ☐ Remove the panel and all tape; check for residue or lifted paint
2. ☐ Lift the unit off the carpet and check underneath for damp or dents
3. ☐ Let carpet pile recover — misting lightly and working the fibres up usually helps
4. ☐ Drain the unit fully and dry the coils in fan mode before storing or moving it
5. ☐ Photograph the window and floor, as you would for any inventory

Our moving guide covers shifting 30kg safely, and our storage guide covers putting it away properly.

Frequently asked questions

Sources

• Shelter — Private renting advice
• Citizens Advice — Renting privately
• GOV.UK — Housing Health and Safety Rating System (excess heat as a hazard)
• GOV.UK — Electrical safety standards in the private rented sector
• Planning Portal — Do you need permission?
• GOV.UK — Fluorinated gases (F-gases): rules
• Electrical Safety First — Overloading sockets

Related reading: our house share guide and seal kits guide.