Portable Air Conditioners: Cool Any UK Room This Summer

At the current price cap of around 26p per kWh, most portable air conditioners cost roughly 26p to 35p per hour to run. A 9000 BTU unit drawing about 1kW works out near 26p/hour, while a more powerful 12000 BTU model is closer to 32-34p/hour. Using eco or sleep mode and a timer noticeably reduces overnight running costs.

A good rule of thumb is around 600 BTU of cooling per square metre of floor space. So a 12m² bedroom suits roughly 7000 BTU, while an 18-20m² living room needs 9000-12000 BTU. Add extra capacity for sunny, south-facing or top-floor rooms, and for spaces with lots of windows or heat-generating appliances. Our BTU calculator gives an exact figure in seconds.

Most UK bedrooms are well served by a 5000 to 9000 BTU portable air conditioner. A small single room of around 10m² is comfortable on 5000-7000 BTU, while a larger double or a warm loft bedroom benefits from 9000 BTU. For bedrooms, also check the decibel rating and choose a model with a quiet sleep mode.

Yes. A refrigerant portable air conditioner produces hot exhaust air that must be vented outside, normally through a window using the supplied hose and window venting kit. Without venting, the unit simply recirculates warm air and won't cool the room. The kits fit most sliding and casement windows, and patio-door and wall-vent solutions are available for awkward setups.

Not for true cooling. Any refrigerant air conditioner needs an exhaust hose to expel heat outside, so a genuinely hoseless cooling unit doesn't exist. The hoseless machines you'll see are evaporative air coolers, which only lower the temperature slightly and lose effectiveness in the high humidity of a British summer. For reliable cooling, choose a hosed portable unit.

The number refers to cooling capacity: 12000 BTU shifts more heat per hour than 9000 BTU, so it cools larger rooms faster. As a guide, 9000 BTU suits rooms up to around 15m², while 12000 BTU is better for living rooms and open-plan spaces up to roughly 20m². The higher-capacity unit uses a little more electricity, costing a few extra pence per hour to run.

No. A single portable air conditioner is designed to cool one room at a time, with doors closed to keep the cold air contained. To cool multiple rooms you'd need a unit in each, or a fitted multi-split system. For whole-home cooling, a multi-room split air conditioning installation is the more effective and energy-efficient option.

The quietest portable air conditioners operate at around 50-54 decibels on their lowest setting — comparable to soft background conversation. Look for models that advertise a low dB rating alongside a dedicated sleep or night mode, which lowers fan speed and dims the display. MeacoCool and other premium brands are popular with light sleepers for exactly this reason.