Every figure checked against its source on 7 November 2026
Air conditioning in a flat: who has to agree, and in what order
Three parties have a say before a unit goes on a flat: the freeholder, under the lease; the planning system, which allows one outdoor unit per block; and on newer estates a management company with covenants of its own. Dartford has 9,762 households in purpose-built flats and 812 in converted houses, and this is the order to take them in.
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Three details and we call you back with the next step.
Why does the freeholder come first?
Because the outside wall is theirs. A lease normally reserves the structure and the exterior to the freeholder, so a bracket, a cored hole and a unit on the elevation need their consent, usually given as a licence to alter. LEASE's guidance is that where the lease allows alterations with consent, that consent should not be unreasonably withheld for an improvement, and that the freeholder may recover reasonable costs for a surveyor, a solicitor and administration. Where the work affects parts they retain, they may ask a premium, and there is no cap on it. Starting with the licence saves weeks. Sources: LEASE; LEASE on charges.
What does planning allow on a block of flats?
One outdoor unit, up to 0.6 cubic metres, as permitted development, provided the building consists wholly of flats, the unit heats as well as cools, it is not on a pitched roof, it sits at least a metre in from the edge of a flat roof and, in a conservation area, it is not on a wall or roof fronting the road. A flat above a shop is not in a building that is wholly flats, so it needs an application from the start. Once the block's one unit has gone to a neighbour, the choice is an application or a monobloc. Source: Planning Portal.
Why do new estates have a third gatekeeper?
Because the developer usually leaves one behind. Ebbsfleet Garden City reached its 5,000th home in December 2025, and most of the flats there and on the newer streets at Stone, Swanscombe and the Bexleyheath town centre are managed by a company that owns the common parts and holds covenants over the elevations. Their rules can be stricter than planning's: a particular finish, a particular position, or nothing at all on a facade that was designed as one piece. Ask for the estate rules before the survey and send them to us. Sources: Ebbsfleet Development Corporation; Wikipedia on Bexleyheath.
What if you rent?
Then the landlord's written agreement comes before anything else, and the landlord may in turn need the freeholder's. Private renting covered 18.1% of Dartford households in 2021, up from 15.9% in 2011, so this is a common position. A landlord fitting a unit for tenants keeps the electrical certificate and the F-gas paperwork with the tenancy file; a tenant who leaves a unit behind usually cannot take it. Source: ONS.
What happens when the answer is no?
You still have two routes. A monobloc through two wall grilles needs a licence to alter for the holes but no outdoor unit, and it heats as well as cools. A portable needs nobody's permission and is the honest stopgap for a tenant. What does not work is fitting first and asking later: a freeholder can require removal and reinstatement at your cost, and so can the council. Our air conditioning in Dartford page covers the wider picture. Sources: LEASE; Mishcon de Reya.
Questions people ask
How long does a licence to alter take?
It depends on the freeholder. A complete application with drawings and the sound calculation moves faster than a vague request, and we supply both.
Can the unit go on a balcony?
Sometimes: the lease must allow it, the balcony must carry the weight, and the sound at the neighbours' windows must pass. All three are checked at the survey.
The flat is a maisonette over a shop. Which rules apply?
The building is not wholly flats, so the outdoor unit is not permitted development and needs an application, as well as the freeholder's consent.
Sources we checked
- LEASE: whether a leaseholder needs the landlord's permission to alter a flat
- LEASE: the charges a landlord may make for consent to alterations
- Planning Portal: when an air source heat pump on a house or flats is permitted development
- Ebbsfleet Development Corporation: the 5,000th home (December 2025)
- Wikipedia: Bexleyheath
- ONS: how life has changed in Dartford, Census 2021
- Mishcon de Reya: the legal checks before installing air conditioning (8 July 2026)
- Census 2021: accommodation type, Dartford
Worth knowing before you ring
With these we can usually tell you on the first call whether the job is simple.
- The postcode
- Whether it is a house, a flat or business premises, and roughly its age
- If you rent or lease, who owns the external wall
- Which room, how big, and the direction its window faces
- Any management company, conservation area or listing that applies
Decided? Our air conditioning in Dartford page covers what we install, what we maintain and where we go.
The services this guide leads to
Home air conditioning
The back bedroom, the new flat with the glass wall, the loft nobody can sleep in: cooled in summer, warmed in winter.
Air conditioning installation
The whole job from the first measurement to the handover of the remote, with every consent checked on the way.
Air-to-air heat pumps
The same wall unit, run the other way: a room heated for pence an hour, with the summer cooling thrown in.
Other guides
What does air conditioning cost to fit and to run?
Where the money goes: the unit, the labour, the wiring, the electricity, and the extras a flat or a new estate brings.
Air conditioning and planning permission: the rules for England
Every permitted development condition in one table, then the twists Dartford's new estates and conservation areas add.
Air conditioning with no outdoor unit: how monoblocs work
The through-the-wall units for flats and blocks that cannot take an outdoor box.
Bedroom air conditioning: what it does for sleep, and what it costs
The sleep threshold, noise at night, sizing and the price of a quiet bedroom.
Cooling a loft conversion: the options that work
Why lofts cook, the free fixes first, then where a unit goes on a dormer.
What size of air conditioner does a room need?
Kilowatts and BTU by room size, with the adjustments that matter.
How to check an air conditioning installer on the F-gas register
The company certificate, the engineer's category and where to look them up.
Portable or fixed air conditioning: which is right for you?
Price, power, noise and running cost, and when a portable is the right call.
Want us to ring you?
A name, a number and a postcode is enough. Say which room if you can. Or ring 01322 952910.