Conservatory Air Conditioning Cost
A conservatory is the hardest room in the house to keep comfortable — a greenhouse in July and an icebox in January. A properly sized air-to-air unit fixes both, and typically costs £1,800–£4,000 installed depending on the size and glazing. We match you with vetted, F-Gas certified local engineers for free, no-obligation quotes.
The quick answer
Air conditioning for a UK conservatory typically costs £1,800–£4,000 fully installed for a single wall-mounted split. A small conservatory (around 8–10 m²) sits at the lower end with a 3.5 kW unit; a large or open-plan conservatory (18–25 m²) needs 5–7 kW and lands towards £3,000–£4,000, occasionally more if two units or a multi-split are required. Because a conservatory has so much glazing, engineers usually size the unit a step larger than they would for an ordinary room of the same floor area. The same unit also heats the space efficiently in winter, so it earns its keep all year.
Conservatory air conditioning cost by size
Indicative UK installed prices for 2026 — a single wall-mounted split, supplied and fitted by an F-Gas certified engineer. A site survey sets the final figure; heavy glazing, a south-facing aspect and a glass roof all push the sizing (and price) up.
| Conservatory size | Typical unit | Installed price |
|---|---|---|
| Small (≈8–10 m²) | 2.5–3.5 kW single split | £1,800–£2,600 |
| Medium (≈12–16 m²) | 3.5–5.0 kW single split | £2,200–£3,200 |
| Large (≈18–25 m²) | 5.0–7.0 kW single split | £2,800–£4,000 |
| Very large / open-plan | Multi-split or two units | £4,000–£6,000 |
Ranges are indicative and cover the unit, materials and labour for a standard fit. Long pipe runs, difficult outdoor-unit positioning or premium brands add to the cost. Get a fixed quote from a local installer before you budget.
Why conservatories need a bigger unit
Cooling is sized on heat gain, not just floor area — and a conservatory gains heat faster than any other room in the house. Roughly 100–150 W of cooling per square metre is the starting rule for a normal room, but a glazed conservatory with a polycarbonate or glass roof can need 50–100% more than that. All that glass lets the sun pour in and gives the heat almost nowhere to hide, so a unit that would comfortably cool a same-sized bedroom will struggle here.
That is why a survey matters. An installer will look at the glazing type, the roof, which way the conservatory faces and whether it is open to the rest of the house, then size the unit to cope with the worst afternoon of the year. Under-size it to save money and you get a machine that runs flat out and never quite wins; size it correctly and it holds your set temperature easily and sips electricity doing so. See our air conditioning installation cost guide for how sizing feeds into price across the whole house.
What it costs to run
Modern inverter splits are cheap to run because they modulate rather than blast on and off. At the summer-2026 electricity rate of about 26p per kWh (rising to roughly 26.3p from 1 October 2026 as Ofgem's price cap increases 4% to £1,723 a year), a typical conservatory unit costs in the region of 20–45p an hour while it is actively cooling — a larger unit on a scorching afternoon at the top of that, a well-shaded room far less. In practice the unit only draws full power for short bursts once the room reaches temperature, so a full day of comfort in a heatwave is usually a pound or two, not a fortune.
The bonus is winter. Because the unit is an air-to-air heat pump, it doubles as an efficient heater, delivering roughly three to four units of heat for every unit of electricity — far cheaper than a plug-in electric heater for a room your central heating was never designed to reach. Our air conditioning running costs guide breaks the maths down in full. Note that air-to-air units fall outside the main £7,500 Boiler Upgrade Scheme, which funds air-to-water heat pumps; a narrower £2,500 BUS grant for air-to-air units opened on 28 April 2026, but it is limited to homes in England and Wales replacing direct electric heating and installed by an MCS-certified firm — check current eligibility with Ofgem.
Three things worth knowing
Portable units rarely cope. A wheel-in portable vents its exhaust hose through a conservatory door or window — which lets hot air leak straight back in, exactly where a conservatory is already losing the battle. For a room this glazed, a fixed split is the only thing that reliably holds temperature. It is the clearest example of the portable-vs-fixed trade-off we cover on the home cooling page.
Planning permission is usually straightforward. The outdoor unit normally falls under permitted development for a house, provided it sits within size and siting limits and is not too close to a boundary; flats, listed buildings and conservation areas have extra rules. Our planning permission guide covers the conditions in detail.
Only use an F-Gas certified installer. Handling the refrigerant in an air conditioning system is a legal requirement to be F-Gas certified — it protects the warranty, the environment and you. Every engineer we match you with holds the right certification. If you are weighing brands, our brand comparison and pages like Mitsubishi Electric and Daikin are a good place to start. For other rooms, compare our bedroom and living room air conditioning cost guides.
Conservatory air conditioning questions
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