Air Conditioning in a Leasehold Flat: Do You Need the Freeholder’s Permission?

This catches people out regularly, usually after the money’s been spent. Here’s what to check before you commit.

Why flats are different

When you buy a leasehold flat you buy a long lease of a defined space — commonly the internal surfaces and the airspace within them. You typically don’t own:

• The external walls
• The roof
• The structure and main fabric
• Common parts, including the exterior of the building
• Often, the window frames themselves

So mounting a condenser on an outside wall or core-drilling through it means altering something belonging to the freeholder. That’s the crux of it.

Check the “demise” clause in your lease — it defines exactly what you hold. Some leases are more generous than others.

The clauses to look for

Get your lease out. You’re looking for:

• Alterations covenant. Frequently prohibits structural alterations outright, or permits them only with the landlord’s prior written consent. Some are “absolute” (no means no); others are “qualified” (consent required, and in many cases not to be unreasonably withheld). The distinction matters a great deal.
• Nuisance and annoyance covenant. Nearly universal. A condenser audible in a neighbour’s bedroom can breach this even if the installation itself was permitted.
• External appearance clause. Many leases prohibit altering the outward appearance of the building, or fixing anything to the exterior — which covers a condenser, a bracket, or a new grille.
• Definition of the demised premises. Where your ownership stops.
• Obligations to obtain statutory consents. Some leases require you to obtain any necessary planning or building control approvals as a condition of consent.

Planning permission is a separate question

Worth being clear: freeholder consent and planning permission are two different things, and you may need both. Getting one doesn’t give you the other.

On the planning side, flats are generally treated more restrictively than houses. Permitted development rights that may cover an outdoor unit on a house are more limited for flats, and rights can be removed entirely by an Article 4 Direction, or by the property being listed or in a conservation area.

Sources on the specific size thresholds disagree with each other, so rather than repeat a figure we can’t verify: check the Planning Portal or ask your local planning authority, both linked below. A pre-application enquiry is usually inexpensive and gives you something in writing.

Our listed buildings and conservation areas guide covers those situations, and our installation law guide covers F-Gas certification and Part P, which apply regardless of tenure.

What you can usually do without any of this

The practical good news for most flat-dwellers:

• A portable unit vented through an opening window using the supplied kit. Nothing is fixed, nothing is drilled, and it comes out when you leave. This is what the overwhelming majority of flat residents end up doing.
• Fans, dehumidifiers and evaporative coolers — no building alteration at all, though see our air cooler comparison on whether the last of those is worth it in UK humidity.
• Internal blinds and curtains. Check whether your lease specifies anything about the appearance of window dressings from outside — some do.

If you want a fixed system: how to approach it

1. Read the lease first. Before getting quotes, before anything.
2. Write to the freeholder or managing agent asking for consent. Be specific: model, dimensions, exact proposed location, noise rating in decibels, and how fixings and any penetration will be made good.
3. Expect to pay their costs. Leases commonly allow the landlord to recover reasonable legal and surveying costs of considering a consent application. Ask what these are likely to be up front.
4. Expect a formal licence. Consent for alterations is usually documented in a licence to alter — a deed, prepared by their solicitor, which you sign and pay for. A verbal “that’s fine” from a managing agent is not the same thing and won’t protect you when the building changes hands.
5. Check the planning position separately.
6. Use an F-Gas certified installer. Legally required for refrigerant work, and freeholders generally require evidence of it along with insurance.
7. Tell your neighbours before it goes in. An objection raised afterwards is much harder to resolve than a conversation beforehand.

The noise issue

Even with consent, noise remains a live risk in a flat, where a condenser may sit metres from someone’s bedroom window.

A neighbour can complain to the council, which has duties under the Environmental Protection Act 1990 in respect of statutory nuisance. If a noise abatement notice is served, you’d be required to address it — and a breach of your lease’s nuisance covenant is a separate matter your freeholder could act on.

Our air conditioning noise guide covers the process from both sides. Practically: specify a quiet unit, don’t site it under or beside a bedroom window, mount it on anti-vibration feet, and consider whether it needs to run overnight at all.

What happens if you install without consent

Being straight about it, since people do ask:

• You may be required to remove it and reinstate the building at your own cost.
• It becomes a problem when you sell. The buyer’s solicitor will raise it, and you may need to obtain retrospective consent or indemnity insurance — usually at short notice and on poor terms.
• Breach of covenant is a matter your freeholder can pursue.
• Your buildings insurance may be affected if unauthorised alterations have been made to the structure. Our home insurance guide covers disclosure principles.

None of that is inevitable, and plenty of installations sit unremarked for years. But it’s a real risk attached to a permanent, visible alteration.

Frequently asked questions

Sources

• LEASE (Leasehold Advisory Service) — lease-advice.org (free advice for leaseholders)
• LEASE — Alterations (consent, licences to alter)
• Planning Portal — Do you need permission?
• GOV.UK — When is permission required?
• GOV.UK — Fluorinated gases (F-gases): rules
• Legislation.gov.uk — Environmental Protection Act 1990, Part III (statutory nuisance)
• Citizens Advice — Housing advice

Related reading: our installation law guide and noise guide.