Do I Need Planning Permission for Air Conditioning? (UK 2026)

For most houses in England, the answer is no — installing an air conditioning unit is treated as permitted development, so you do not need a planning application. Since the rules were updated on 29 May 2025, an air conditioner (which is an air-to-air heat pump running in reverse) is covered by the same permitted-development class as air-source heat pumps, as long as the outdoor unit is installed correctly.

The catch is that permitted development is conditional. The outdoor condenser must comply with the MCS 020 standard, and your property must not fall into one of the exception categories — most importantly listed buildings, conservation areas, flats and Article 4 areas. Get one of those wrong and what looked like a no-permission job suddenly needs the council's sign-off.

MCS 020 is the technical standard that decides whether an outdoor unit qualifies for permitted development. The headline figure is noise: the unit must produce no more than 42 dB(A) when measured one metre from the nearest neighbour's habitable-room window. In practice that means the condenser has to be sited and specified so it is genuinely quiet at the boundary — position, distance and the unit's own sound rating all matter.

The 2025 update also removed the old rule that forced the unit to sit at least one metre from the property boundary, and it raised the permitted outdoor-unit volume to 1.5m³ for a house. A good installer runs the MCS 020 noise assessment as part of the design rather than guessing — if the unit can't meet 42 dB(A) at the neighbour's window, permitted development falls away and you'd need to apply.

Permitted development rights are stripped back or removed entirely in several common situations. You should assume you need permission (or specialist advice) if any of these apply:

Listed buildings need listed building consent for an external unit — and often for the internal pipework runs too. Conservation areas restrict where the outdoor unit can go: you generally cannot fix a condenser to a wall or roof slope that fronts a highway without prior approval. Flats and maisonettes are not covered by the heat-pump permitted-development class at all, and the permitted outdoor-unit volume is capped lower (around 0.6m³), so balcony and external siting almost always needs landlord and planning consent. Article 4 areas are zones where the council has formally removed normal permitted-development rights — minor external changes that would be allowed elsewhere require a full application here.

Surrey is exactly the kind of patch where the exceptions bite, because it has a high concentration of conservation areas, listed buildings and the Surrey Hills National Landscape (AONB). In Guildford, the borough has around 40 conservation areas, and the Charlotteville & Warren Road area carries an Article 4 direction — so a condenser on a street-facing elevation of a Victorian terrace there needs express permission rather than being automatic.

It's a similar story across the county. Farnham has an Outstanding Conservation Area covering much of its Georgian town centre plus hundreds of listed buildings; parts of Dorking, Leatherhead and Brockham (Mole Valley) sit under Article 4 directions. The practical answer in these areas is usually to site the outdoor unit to the rear or a courtyard, out of sight of the highway — which often keeps you compliant while still getting the cooling you need. As your local installer we check the planning status of your specific address before quoting, so there are no surprises.

This is a common and important misconception, so to be completely straight with you: no, you cannot get a government grant for air conditioning. The Boiler Upgrade Scheme (BUS) only funds air-to-water heat pumps, ground-source heat pumps and biomass boilers — it does not cover the air-to-air systems used for cooling, even though an air conditioner is technically a heat pump.

Anyone telling you there's a grant for standard air conditioning is mistaken. Where we can genuinely help on cost is finance: Tempest offers FCA-regulated payment plans through Phoenix Financial (subject to status), so you can spread the cost rather than relying on a grant that doesn't exist for this technology.

Costs vary with the size of the system rather than the planning route, though Surrey and the South-East tend to run roughly 10–20% above the UK average. As a guide, a single split system is typically £1,500–£3,000, a multi-split covering three to four rooms £3,500–£7,000, and a ducted whole-home system £6,000–£20,000.

The smartest first step is a site survey. We confirm whether your property is permitted development or needs an application, run the MCS 020 noise check, and design the unit position to keep it compliant and discreet. If consent is required — for a listed building or conservation area — we'll tell you up front and help with the paperwork rather than leaving you to navigate the council alone.