Air conditioning units
Whether you want to cool a stuffy bedroom this week or keep the whole house comfortable for years, there is an air conditioning unit that fits. Most UK homes choose between a plug-in portable you can set up yourself and a fitted wall-mounted split, with multi-split, ducted, floor-standing and cassette systems for bigger or awkward spaces. Work out the type and size you need, then compare the models we review independently on what they cost to buy and run.
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Wall-mounted air conditioners
The default way to cool and heat a single room: a wall-mounted air conditioning unit indoors and a condenser outside. Quiet, efficient and, on a reverse-cycle model, a low-cost heater in winter too.
Multi-split systems
Cool and heat several rooms from a single outdoor unit. Tidier than multiple separate systems, and you can mix wall, floor, cassette and ducted indoor units on one condenser.
Portable air conditioners
Plug-in cooling with no installation, no planning and no F-Gas engineer. Here is how portable units really perform, what they cost to run, and when a fixed split is the smarter buy.
Ducted air conditioning
Near-invisible cooling and heating. The indoor unit hides in a loft or ceiling void and delivers air through discreet grilles, so only the grilles show. The tidiest option, and the priciest.
Floor-standing air conditioners
A fixed floor-mounted console that sits low against a wall, ideal where there is no room for a high wall unit. Great for glazed rooms and heating-led use, with warm air delivered at floor level like a radiator.
Ceiling cassette air conditioning
A unit recessed into the ceiling, flush behind a slim grille, that spreads air evenly across the room. Ideal for open-plan spaces and loft rooms, as long as there is enough ceiling void to hide it.
Which air conditioning unit is right for you?
Start with how you want to use it. A portable air conditioner plugs into a normal socket and vents hot air out of a window through a hose, so there is nothing to install and nothing for a landlord to object to. It is the quick fix for renters and the odd hot spell, though it is noisier and costs more to run than a fitted system.
If you own your home and use the room a lot, a wall-mounted split is the default choice. A slim indoor unit sits high on the wall, a condenser sits outside, and an F-Gas engineer connects the two, usually in about a day. It is quiet and efficient, and a reverse-cycle model heats the room cheaply in winter as well.
To cool several rooms, a multi-split system runs two to five indoor units from one outdoor condenser, which keeps the outside of the house tidy. Ducted air conditioning goes a step further and hides the hardware in the loft or ceiling so only slim grilles show; it is the priciest option and far easier to fit during building work than afterwards.
Two less common types solve awkward rooms. A floor-standing unit sits low against a wall much as a radiator does, which suits conservatories and rooms with lots of glass or no clear high wall, while a ceiling cassette recesses into a ceiling void and spreads air evenly across an open-plan space.
Whichever type you go for, size it to the room. Allow roughly 0.1 kW of cooling per square metre for a standard room and about 0.15 kW for kitchens and conservatories, or let our BTU calculator do the sums for you.
On price, a portable is the cheapest way in, while a single-room wall-mounted split typically costs around £1,500 to £2,500 fitted. Our guide to how much air conditioning costs breaks down what you can expect to pay for each type.
Top-rated this month
Perfera FTXM-A
★★★★★ ★★★★★ 4.52.0–7.1 kW · up to A+++ · from 19 dB(A) · R32
supplied & fitted, 2.5 kW single split (standard install) from £1,888
Mitsubishi Electric MSZ-LN
★★★★★ ★★★★★ 4.52.5–6.1 kW · up to A+++ · from 19 dB(A) · R32
unit only, 2.5 kW (LN25), on back-order, fitting extra £1,186.80
Stylish FTXA
★★★★★ ★★★★★ 4.42.0–5.0 kW · up to A+++ · from 19 dB(A) · R32
supplied and fitted, 2.5 kW, standard 3 to 5 m install from £2,146
Daikin 3MXM Multi-split
★★★★★ ★★★★★ 4.35.2 kW class · up to 3 rooms · R32 · A+++/A++
outdoor unit only, 3MXM52A9 5.2 kW, inc VAT, out of stock £1,944.00
Pinguino PAC EX100 Silent
★★★★★ ★★★★★ 4.210,000 BTU · 2.5 kW · A++ (EER 3.6) · R290 · from 49 dB(A)
inc. VAT, reduced from £949.99, sold out at our last check £868.95
Midea PortaSplit
★★★★★ ★★★★★ 4.212,000 BTU (3.5 kW) · R32 · SEER 6.1 · from 39 dB(A) indoor
12,000 BTU heat-pump model, in stock, 2 to 4 working days delivery £1,175Shop by brand
Daikin
★★★★★ ★★★★★ 4.7One of the biggest names in air conditioning and a favourite with UK installers, for its class-leading efficiency and wide choice of designer finishes.
Mitsubishi Electric
★★★★★ ★★★★★ 4.6Superb build quality and class-leading quiet running. The premium pick when near-silent bedroom operation matters most.
Panasonic
★★★★★ ★★★★★ 4.5A big-four Japanese brand whose Etherea range pairs top-tier efficiency with nanoe X air purification that runs even when you are not heating or cooling.
Toshiba
★★★★★ ★★★★★ 4.4Premium Japanese engineering with a twist: the Haori wears a changeable fabric fascia and the Daiseikai 10 is among the most efficient units you can buy.
Fujitsu
★★★★★ ★★★★★ 4.3A long-established, installer-trusted Japanese split-system brand. Quietly excellent, broad range, and no relation to Fujitsu the computer company.
Samsung
★★★★★ ★★★★★ 4.2Draught-free Wind-Free cooling and the best smart-home integration in air conditioning, in distinctive designs at a competitive price.
Air conditioning units: common questions
What is the best type of air conditioning unit for a home? +
For most homes it is a wall-mounted split, because it is quiet, efficient and, as a reverse-cycle unit, heats as well as cools. A portable makes more sense if you rent, cannot fit an outdoor unit or only need cooling for a few hot weeks a year, and a multi-split or ducted system is the better answer once you want several rooms done.
How much does an air conditioning unit cost to buy and install? +
A single-room wall-mounted split typically costs around £1,500 to £2,500 fitted, depending on the model and how straightforward the installation is. A portable costs far less because there is nothing to install, and systems that serve several rooms cost more, so get a written quote that includes the outdoor unit position and pipe run before you commit.
What size air conditioning unit do I need? +
Allow roughly 0.1 kW of cooling per square metre for a standard room, rising to about 0.15 kW for kitchens and conservatories. A 20 m² bedroom therefore needs about 2 kW, roughly 6,800 BTU (1 kW is 3,412 BTU per hour), and you round up to the next standard size; add 10 to 15% for a portable. Strong sun, high ceilings and poor insulation all push the figure up, and our sizing guide walks through the adjustments.
Can I install an air conditioning unit myself? +
A portable, yes: it plugs into a normal socket and the only fitting is the window kit. A fitted split is different, because connecting the refrigerant pipework must be done by an F-Gas certified engineer. Our guide to installing air conditioning yourself explains where the line sits, and when you are ready you can compare quotes from local installers.
Does an air conditioning unit need planning permission? +
A portable does not. In England, a reverse-cycle unit that heats as well as cools can count as permitted development if it meets the conditions on size, siting and noise, but a cooling-only unit generally needs full planning permission. Flats, listed buildings and conservation areas are treated more strictly, and the rest of the UK has its own rules, so check with your local planning authority first. Our planning permission guide has the detail.
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