If the freeholder or managing agent says no, the lease is the constraint that matters on the day. Planning permission, or permitted development, does not rewrite a covenant against alterations or external plant. Ask which clause they are relying on, and whether a rear position, a noise limit or a licence to alter would change the answer. Some freeholders refuse all condensers. Drilling anyway is how you lose the argument and the deposit. F-gas installers should not start on a refused wall.
The clause, not the porter's mood
Many residential leases ban alterations, anything fixed to the exterior, and items on balconies or roofs, sometimes in words that clearly catch an outdoor unit and sometimes in words a solicitor has to read. Get the refusal and the clause in writing. A verbal no from a porter is a warning, not the document. Citizens Advice sets out the general consumer side of getting home improvements done. It does not rewrite your lease.
Councils and freeholders answer different questions. The Planning Portal may describe a rear unit that does not need planning permission. The freeholder may still withhold consent. You need the one your building actually requires, which for a flat is usually both.
A quieter drawing, a tribunal, and the portable that remains
Some agents are refusing the idea, not a specific drawing. A short pack can help: outdoor location off the street, manufacturer's sound data, anti-vibration mounts, condensate to your own drain, and a promise to remove the unit at the end of the term if that is what they want. Keep it factual.
Offer to pay their reasonable consent costs if the lease says that is how alterations are approved. Do not offer to hide trunking on a street elevation in a conservation area. That trades one refusal for another.
A clear prohibition is a property right. Challenging it can mean a leasehold adviser and, in some cases, a tribunal. That is outside an air conditioning survey. Do not use this page as a litigation plan, and do not let an installer tell you the freeholder is bluffing.
If external plant is impossible, ask whether the lease allows internal work and wall cores for a monobloc. Often it does not, because the cores are still an alteration to the fabric. Energy Saving Trust describes air-to-air heat pumps. None of that description overrides a refused wall. GOV.UK F-gas rules still apply if someone later opens a circuit.
Price only what a yes would allow
Send the written refusal or the lease extract before anyone quotes pipe lengths as if the wall were free. The survey can still say what would be technically possible if consent appeared. It should not book a commissioning date.
Attach whatever the freeholder sent. A split can be priced only as a fallback, with a monobloc comment if holes might be allowed. F-gas work waits until someone with authority has said yes.
Frequently asked questions
Can I fit the unit if the council says planning permission is not required?
Not if the lease or the freeholder forbids it. Planning and landlord consent are separate. You can need either, or both.
Should I install and apologise later?
No. Unauthorised work can breach the lease, and removing a charged split later needs an F-gas recovery, not a hacksaw.
Will a quieter brand change a blanket ban?
Sometimes a noise concern can be met with siting and data. A ban on all external alterations will not care whether the badge is Daikin or Mitsubishi. Read the clause.
Is a portable the fallback when external plant is banned?
Often a monobloc is also refused, because the cores are still an alteration to the fabric. A portable with a window kit is the remaining honest option for a tenant, with the usual noise and efficiency limits.
Core buying guides
Start with these high-intent guides, then dig into the rest of the library.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.