Can I install air conditioning in a flat?

Start with the lease, not the technology. Almost every London lease reserves the external walls, roof and often the balcony to the freeholder, so fixing a condenser to any of them without consent is a breach, however invisible the unit. The consequences are real: freeholders can and do require removal, and an unconsented unit surfaces at sale time when the buyer's solicitor asks about alterations.

The good news is that consent is granted routinely when requested properly. Managing agents say yes to specific, documented proposals: this unit, this sound level, this fixing method, this insurance. They say no, or nothing, to vague enquiries. We prepare the technical pack that turns a request into an approval, and in buildings where a previous installation was approved we propose the same design, because precedent is the fastest route through.

Physically, most flats have a workable position. Balconies take compact condensers on anti-vibration mounts with the condensate piped to a drain. Flat roofs work with landlord consent and safe access. Rear walls and lightwells serve mansion blocks. Where a building genuinely has nowhere, a through-wall monobloc unit needs only ducting through the wall, an honest second-best that beats another summer of portable units.

Costs run £200 to £400 above house installs for the access and consent work, £1,800 to £3,000 for a single room. Timescale is dominated by consent, weeks rather than days; the install itself remains one day.

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