Single room air conditioning: which type suits one room?
For one room in a UK home, a wall-mounted split system is usually the best choice: it's the quietest, the cheapest to run and it heats in winter too. A floor console suits lofts and low walls, a portable suits short-term or occasional use, and a through-wall unit suits a room with nowhere for an outdoor unit. With us, one room starts at £1,850 fitted, inc. VAT.
- one room, 2.5 kW, fitted, inc. VAT
- From £1,850
- premium 2.5 kW wall unit, quietest
- 19 dB(A)
- an hour to cool, 2.5 kW split
- 7p–17p
- to fit one wall unit
- 4–8 hours
Your four options for one room
Air conditioning for a single room comes in four main types. Two are split systems, with a quiet indoor unit and the noisy compressor in a small outdoor unit. Two keep everything inside the room.
- Wall-mounted split: a slim unit high on the wall, piped to an outdoor unit through the wall behind it
- Floor-standing console: the same split system, but the indoor unit sits low on the wall like a radiator
- Portable: a unit on wheels that blows its hot air out through a hose in a window
- Through-wall unit: one indoor box with no outdoor unit, breathing through two holes in the outside wall
Single room air conditioning compared
Typical figures for a unit sized for a bedroom or small living room. Noise figures are the manufacturers' own, in the quietest to highest fan settings.
| Type | Wall split | Floor console | Portable | Through-wall |
|---|---|---|---|---|
| Indoor noise | 19 to 41 dB(A), Daikin Perfera 2.5 kW | 20 to 38 dB(A), Daikin Perfera floor 2.5 kW | 52 to 54 dB, Meaco 9,000 BTU | 32 to 41 dB(A) at 2 m, Olimpia Splendid Unico Pro |
| Running cost | About 7p to 17p an hour to cool, 2.5 kW | Similar to a wall split of the same size | About 26p an hour: Meaco lists 1,005 W in cooling | Generally higher than a split for the same cooling |
| Cost | From £1,850 fitted, inc. VAT | From £2,350 fitted, inc. VAT | About £250 to £600 to buy | We don't fit them, so ask a supplier for a fitted price |
| Outside | Small outdoor unit, pipes through the wall behind the unit | Small outdoor unit, pipes through the wall behind the unit | Hose out of a window or vent while it runs | Two grilles on the outside wall, holes of 162 or 202 mm |
| Heating | Yes, every system we fit | Yes, every system we fit | Some models | Some models |
| Planning | Usually permitted development if every Class G rule is met | Same rules as a wall split | Not fixed to the building | Listed buildings need consent; in a flat, the freeholder's too |
| Best for | Bedrooms, studies and living rooms used most days | Lofts with sloping ceilings, or under a window | Occasional use, or a rented room you can't alter | A room with truly nowhere for an outdoor unit |
Manufacturers measure noise in different ways and at different distances, so treat the figures as a guide. Running costs at the Ofgem price cap for October to December 2026, 26.32p per kWh. Portable prices are a typical market range.
Wall-mounted split: the usual answer
A wall-mounted split is what most people picture when they think of air conditioning, and for one room it's hard to beat. The noisy parts are outside, so the indoor unit runs at 19 dB(A) on its quietest setting in the premium 2.5 kW ranges from Daikin, Mitsubishi Electric, Panasonic and LG. It cools a room quickly, controls humidity, and heats it in winter for about a fifth of the cost of plug-in electric heaters, per unit of heat.
We fit it with the pipes going straight through the wall behind the indoor unit, so nothing shows on your inside wall. Outside, the pipes run in neat trunking to the outdoor unit. Most single rooms are fitted in a day.
Floor console: for lofts and low walls
A floor console is the same split system with a different indoor unit. It sits low on the wall, about the size of a small radiator: Daikin's Perfera floor unit is 600 mm high and 750 mm wide. It suits loft rooms where the sloping ceiling leaves no high wall, and rooms where the only free wall is under a window.
It's just as quiet. Daikin lists 20 dB(A) on silent and 25 dB(A) on low for the 2.5 kW Perfera floor unit in cooling. With us it starts at £2,350 fitted, inc. VAT.
Portable air conditioner vs split system
A portable is the cheapest way to cool one room, and it needs no installer. But it keeps the compressor in the room with you. Meaco, for example, lists 52 dB on the lowest fan speed for its 9,000 BTU portable, against 25 dB(A) on low for a premium 2.5 kW wall unit. It also draws more power: Meaco lists 1,005 W in cooling, about 26p an hour at the current price cap, while a 2.5 kW split costs about 7p to 17p an hour.
The hose is the other catch. The portable pushes hot air out of the window, and warm air from outside is drawn back in through gaps to replace it. Portable and through-wall units are also given energy labels on a different scale from split systems, so an A on a portable can't be compared with an A++ on a split. A portable makes sense for a few hot weeks, or a rented room you can't alter. For a bedroom you use every summer, a split is quieter and cheaper to run.
Through-wall units: no outdoor unit
Through-wall units, such as Olimpia Splendid's Unico range, put everything in one indoor box on an outside wall. They breathe through two holes in the wall, 162 or 202 mm across for the Unico Pro, finished with grilles outside. There's no outdoor unit to place, which can help where there's no yard, balcony or wall space outside.
The trade-off is noise and efficiency. With the compressor inside the room, Olimpia Splendid lists 32 to 41 dB(A) for the Unico Pro, measured 2 metres away, against 19 dB(A) for a premium wall split at its quietest. The systems we fit all have an outdoor unit. If your room truly can't have one, we'll tell you honestly rather than sell you something that doesn't fit.
What size unit for one room?
Most bedrooms and studies need a 2.5 kW unit, most living rooms 3.5 kW, and big open-plan rooms or lofts 5 kW. Sun through big windows, high ceilings and loft roofs push the size up. Bigger isn't better: an oversized unit costs more to run and is louder at its quietest setting. Our sizing guide has the full rule of thumb, and the survey confirms the right size for your room.
How much is air conditioning for one room?
Starting prices for one room, fitted, with 5 m of pipe. Home prices include VAT. The cost guide explains what can add to them.
- from£1,850inc. VAT
A bedroom or study
2.5 kW wall unit, 5 m pipe, fitted in a day
- from£2,050inc. VAT
A living room
3.5 kW wall unit
- from£2,450inc. VAT
Open plan or a loft
5 kW wall unit
- from£2,350inc. VAT
Floor-standing unit
2.5 kW console
- from£250inc. VAT
Premium range upgrade
Quieter, more efficient unit
- from£550inc. VAT
Design range upgrade
Daikin Emura, Mitsubishi Electric Zen, LG Artcool
Planning for a single unit
In England, a heating-capable unit on a house is permitted development under Class G, with no planning application, as long as every rule is met. A semi-detached or terraced house can have one heat pump, and a detached house two. The outdoor unit can be up to 1.5 m³, it must pass the MCS 020(a) noise calculation of 37 dB(A) at a neighbour's window, and it must not be used solely for cooling.
Position matters too. In a conservation area or World Heritage Site it can't go on a wall or roof facing a highway. Elsewhere, it can't go above ground-floor level on a wall facing a highway. Listed buildings always need consent. Our planning checker looks up your postcode, and our planning guide sets out every rule.
One room in a London flat
Class G covers blocks of flats too, with tighter limits: one heat pump per block, with an outdoor unit no bigger than 0.6 m³. If the block already has one, a second needs planning permission. Most leases also need the freeholder's written consent, whatever the planning position, and managing agents can take weeks to reply, so ask early.
In a flat the outdoor unit usually goes on a rear wall bracket, a balcony, a flat roof, or a lightwell or plant area the managing agent sets, if the lease allows it. Our flats page explains how to put the consent request together.
If the room is a bedroom
A bedroom needs a quiet model, the right size and a position where the air never lands on the bed. A correctly sized 2.5 kW premium unit on quiet mode runs at about 19 to 20 dB(A), according to the manufacturers. Cool the room before bed, then let the sleep setting take over. Our bedrooms page covers placement and sleep temperatures.
Single room air conditioning questions
What is the best air conditioning for one room?
For a room you use most days, a wall-mounted split system. It's the quietest and cheapest to run, it heats as well as cools, and it's fitted in a day. A floor console is the better fit for a loft with sloping ceilings, and a portable suits occasional use or a rented room you can't alter.
How much is air conditioning for one room in the UK?
With us, from £1,850 for a 2.5 kW wall unit in a bedroom or study, £2,050 for a 3.5 kW living room unit, £2,450 for a 5 kW unit and £2,350 for a floor console, all fitted and inc. VAT. Portables cost less to buy but more to run.
Is a portable air conditioner as good as a split system?
No. A portable keeps the compressor in the room, so it's much louder, and it uses more electricity for the cooling you get. Its hose pushes hot air out of the window while warm air leaks back in. It's fine for a few hot weeks, but a split is better for a room you use every summer.
Can I have air conditioning in one room without an outdoor unit?
Yes, with a portable or a through-wall unit. Both keep the compressor inside, so they're louder indoors and generally less efficient than a split system. Through-wall units need two large holes in an outside wall. The systems we fit all have an outdoor unit.
Do I need planning permission for air conditioning in one room?
Often not, for a heating-capable unit on a house in England that meets every Class G rule on size, position and noise. A cooling-only unit, a listed building or a street-facing wall in a conservation area all need permission. Flats also need the freeholder's consent. We check at the survey.
What size air conditioner do I need for one room?
Usually 2.5 kW for a bedroom or study, 3.5 kW for a living room and 5 kW for a large open-plan room or loft. Sunny glazing, high ceilings and loft roofs push the size up, and the survey confirms it.