Home Air Conditioning
UK summers have changed, and so has home cooling. A modern wall-mounted split cools your bedroom in July, heats it efficiently in January, and costs pennies an hour to run. We match you with vetted, F-Gas certified local installers — free quotes, no obligation.
The case for cooling a UK home
British houses were designed to keep heat in, which is exactly why they perform so badly in a heatwave. Well-insulated modern homes and loft conversions trap summer heat, and the rooms that suffer most are the ones you can least escape: bedrooms at night, lofts under hot roofs, conservatories that turn into greenhouses, and home offices where you have to function through the hottest hours of the day.
Fans move warm air around; only air conditioning actually removes heat and humidity. And because a modern split is an air-to-air heat pump, the same unit becomes an efficient heater for the rest of the year — one installation, year-round comfort.
Which rooms, and what size?
The working rule of thumb is 100–150 W of cooling per square metre of floor area — glazing, aspect and roof exposure decide where in that range a room sits. A survey fixes the final number, but here is how typical rooms shake out.
Bedrooms
The highest-value room to cool — sleep quality transforms in a heatwave. A typical double bedroom needs a compact 2–2.5 kW unit running whisper-quiet overnight.
Loft rooms
Heat rises and roofs bake, so lofts are usually the hottest rooms in the house. Size at the top of the range and let the same unit heat the room cheaply in winter.
Conservatories
All that glazing means brutal summer gains and cold winters — the classic case for an air-to-air unit that works hard in both directions.
Living rooms & offices
A 20 m² lounge or a home office lands around 2–3 kW. For several rooms, a multi-split serves them all from one outdoor unit.
Portable vs fixed air conditioning
Portable units are tempting because there's no installation — but the comparison over even one hot summer is not close.
| Portable unit | Fixed wall-mounted split | |
|---|---|---|
| Effectiveness | Limited — the exhaust hose through an open window lets warm air leak straight back in | Sealed system; removes heat properly and holds the set temperature |
| Noise | Compressor is in the room with you | Indoor unit ~19–30 dB(A); compressor lives outside |
| Efficiency | Poor — much of the cooling is lost re-drawing warm air | High; inverter-driven, sized to the room |
| Heating | No useful winter role | Doubles as an efficient air-to-air heat pump (SCOP 3.5–4+) |
| Installation | None — plug in | Professional install by an F-Gas certified engineer |
| Lifespan & warranty | Short-lived appliance | Long service life; 5–7 yr warranties on premium brands via accredited installers |
If you need cooling for one week a year, hire a portable. If you'll use it every summer — and want cheap heating too — a fixed split wins on every measure that matters.
Quiet in the room, pennies on the meter
Noise. Modern indoor units run at roughly 19–30 dB(A) depending on fan speed — the low end is close to the threshold of hearing, quieter than a whisper. The outdoor unit does the noisy work, which is why placement matters: a good installer sites it away from your bedroom window and your neighbour's boundary, on anti-vibration mounts.
Running costs. A 2.5 kW-class unit draws around 0.7–0.9 kW while cooling. At roughly 26p/kWh under the July–September 2026 price cap (£1,663 a year for typical dual-fuel use), that's about 18–23p per hour — a full evening's cooling for less than a pound. Ofgem confirms the October–December 2026 cap on 26 August 2026, and suppliers are forecasting a modest rise of around 3–4%, so expect the per-hour figure to edge up slightly this autumn. In winter the same unit heats with a SCOP of 3.5–4+, delivering three-and-a-half to four kilowatts of heat for each kilowatt of electricity. There is also a 2026 change worth knowing: since 28 April 2026, air-to-air heat pumps have qualified for a £2,500 Boiler Upgrade Scheme grant in England and Wales — but only where the unit is the home's primary heating and no fossil-fuel boiler is retained, so most homes adding air conditioning for summer cooling alongside an existing boiler will not qualify. Ask your installer to confirm eligibility at survey.
Planning permission, briefly
For most houses, a domestic wall-mounted unit is permitted development — no planning application needed — provided the siting and size conditions are met, which is one of the things a competent installer checks at survey. The two big exceptions: conservation areas and listed buildings, where consent is needed before anything goes on a wall. Flats and leasehold properties should also check the lease and freeholder position.
The full detail, including the conditions and the exception cases, is in our guide: air conditioning planning permission in the UK.
Sources & methodology
- Running-cost basis: electricity ~26p/kWh (July 2026 price cap, £1,663/yr typical dual fuel); 2.5 kW-class unit drawing ~0.7–0.9 kW → ~18–23p/hour.
- Install pricing: single split £1,500–£3,000 (typically £1,800–£2,500); multi-split £2,800–£5,000 (2 rooms) / £4,500–£7,500 (3 rooms).
- Sizing rule of thumb: ~100–150 W cooling per m²; indoor unit noise ~19–30 dB(A).
- Planning: domestic units usually permitted development within siting/size limits; conservation areas and listed buildings need consent.
Frequently asked questions
Sleep cool this summer
Tell us which rooms you want conditioned and we'll match you with vetted, F-Gas certified installers near you. Compare free quotes with no obligation.