Rules last checked on 5 November 2026
Can you have air conditioning in a flat?
Usually yes, but not without asking. A flat needs agreement from whoever owns the outside walls, and the planning rules allow only one outdoor unit on a block. In Harlow, where nearly three in ten households rent socially, that often means the council. This guide sets out who to ask, and in what order, before you spend anything.
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Start with the lease or tenancy
LEASE, the government-funded advice body, says most leases have a clause on alterations. Some allow changes with consent, and consent should not be unreasonably withheld if the work is an improvement. Others ban alterations outright, which would mean asking the landlord to vary the lease.
The outside walls matter most here. LEASE notes that external and structural walls and the roof are usually the landlord's retained property, and on those the landlord does not have to consent and can ask for a premium. So read the clause first and get any consent in writing. Tenants need their landlord's written agreement before anything goes on a wall.
If your landlord is Harlow Council
The council tells both tenants and leaseholders the same thing: do not begin work until you have its written permission. Applications go to your Housing Officer in writing with detailed plans and a specification, and tenants also need a method statement and insurance details. The costs of applying are not refunded, even if the answer is no. The council's pages do not mention air conditioning, but tenants have to ask about satellite dishes and aerials, so expect an outdoor unit to be treated in the same way or more carefully.
The planning limit on a block
Under permitted development, a whole block gets one air source heat pump, with an outdoor unit no larger than 0.6 cubic metres. If a neighbour has already used that allowance, a second is likely to need a planning application. The noise calculation and the rule against cooling-only use apply here as they do on a house. See the planning guide.
Where can the outdoor unit go?
- A balcony, if the lease allows it and the air can move freely. Check how close it would be to a neighbour's window.
- A flat roof, with the freeholder's agreement and safe access for servicing, and a metre clear of each edge.
- The ground or a low wall, if you are close enough for a practical pipe route.
- High on an outside wall, usually the costliest choice, and ruled out by the planning rules above ground-floor level on a side facing a road.
Taller blocks and converted offices
Harlow has flats of many ages, from The Lawn of 1951 to the office blocks that have since been converted, including 13-storey Terminus House, which the council agreed to buy in 2025 for redevelopment. High up, access decides the cost, because someone has to reach the outdoor unit safely, both to fit it and to service it. Sealed or communal façades may rule out a new hole altogether. Ask your managing agent early for the rules on external plant.
When a portable unit is the honest answer
If you cannot get consent, a portable unit needs no permission from anyone, apart from a window you can vent through. It will not perform like a split system, but it may get you through a hot spell. See portable or fixed.
Questions people ask
Can the freeholder charge for consent?
Yes. LEASE says a landlord may charge a reasonable sum for expenses properly incurred, such as surveyor or solicitor fees, and that unreasonable charges can be challenged at a tribunal.
Can my neighbour and I share one outdoor unit?
In theory a multi-split can serve more than one room, but sharing across two flats raises questions about power, access and ownership. Talk to the freeholder first.
Does this apply to a maisonette?
The same questions apply if you have a lease or a landlord. Check who owns the outside walls.
Sources
- LEASE: do I need my landlord's permission to alter my property?
- LEASE: consent to alterations, what charges can be justified
- Harlow Council: council tenant alterations
- Harlow Council: leaseholder alterations
- ONS: how life has changed in Harlow, Census 2021
- Planning Portal: heat pumps and when you need permission
- Wikipedia: The Lawn, Harlow
- Harlow Council: the council agrees to buy Terminus House (June 2025)
Useful to have ready
A few details about the building let us say more on the first call.
- Your postcode
- House, flat or business premises
- Which rooms, and roughly how big
- Which way the windows face
- Who owns the outside walls, if you rent or lease
Want this done rather than read about? Air conditioning in Harlow shows what we fit, service and repair, and where we go.
If you want this done
Domestic air conditioning
For the bedroom that stays hot after dark, and rooms like it.
Air conditioning installation
The whole job, stage by stage, from first visit to handover.
Air-to-air heat pumps
One unit for winter warmth and summer cooling. No radiators.
Other guides
How much does air conditioning cost?
Every cost from purchase to running it, with the working shown.
Does air conditioning need planning permission?
The national conditions, the noise limit and Harlow's protected streets.
Can air conditioning heat your home?
Reversing the system, running costs against gas and electric, and where it falls short.
What size air conditioner do you need?
Floor area, kW and BTU, and what shifts the answer.
How to check an installer's F-gas certificate
Two certificates worth asking for, plus leak checks and refrigerant bans.
Portable or fixed air conditioning?
Price, noise, cooling power and which suits your room.
Ask us to ring you
Leave a number and we will call to talk about the job. Or ring 01279 744503.