Bedroom Air Conditioning

A bedroom that will not cool down at night is one of the hardest rooms to live with. Rooms at the back of the house, loft rooms and bedrooms above a garage can stay warm long after the sun has gone down. An open window often lets in noise and light as well as air.

The Sleep Charity suggests a bedroom temperature of 16 to 18°C for sleep. On a warm night, rooms under the roof or facing the evening sun can stay well above that. A wall-mounted air conditioning unit brings the room down to the temperature you set and holds it there quietly through the night. The same unit heats the room in winter.

How Quiet Is Bedroom Air Conditioning?

Noise is usually the first concern for a bedroom, and the answer depends on the model and the fan speed.

The quietest wall units are rated at 19 dB(A) on their lowest fan setting. That includes the Mitsubishi Electric MSZ-LN and MSZ-AP ranges and Panasonic's Etherea in quiet mode. The World Health Organization's guidance for sleep is to keep continuous background noise in a bedroom below 30 dB(A), and a good unit on a low setting is well inside that.

Higher fan speeds are louder, so we size the unit to reach the temperature you want without running flat out. Many models also have a night mode that lowers the fan speed, dims the display and reduces outdoor unit noise. Our guide to the quietest air conditioners compares the figures.

What Size Unit Does a Bedroom Need?

Most bedrooms need a unit of 2.0 to 2.5 kW. A large main bedroom, a loft room with big roof windows or a room that gets strong afternoon sun may need 3.5 kW.

Bigger is not better. A unit that is too large cools the room quickly, then switches off and on, which can leave the air feeling clammy. We calculate the right size for each room at the survey. Our guide to what size air conditioner you need explains how.

Where Should the Unit Go?

• Not blowing on the bed. We position the unit so that air moves across the room rather than straight at you while you sleep.

• High on a wall, with space around it. Wall units need a clear gap above and to the sides for airflow, so they often go above a door or window or high on a side wall.

• On an outside wall where possible. This keeps the pipe run short and neat. Where that is not possible, pipework can run through a cupboard, the loft or a neat trunking route.

• The outdoor unit goes on a rear wall, a flat roof or the ground, positioned with your neighbours' bedrooms in mind.

The water the unit removes from the air drains outside through a small pipe or, where there is no natural fall, through a small pump. We agree every position with you at the survey.

Heating in Winter

The systems we fit for homes heat as well as cool. A bedroom unit is an efficient way to warm a cold room on winter mornings without heating the whole house. You can set it on a timer from the remote or, on many models, an app. Read more about air conditioning as a form of heating.

What Does Bedroom Air Conditioning Cost?

As a guide, one room typically starts from around £2,500 installed. The final price depends on the unit, the pipe route and the electrical supply, and we give you a clear written quote after a free survey. Most single-room systems are fitted in a day.

Cooling several bedrooms? A multi-split system runs up to five or six indoor units from one outdoor unit, depending on the model.

Frequently Asked Questions

Is it safe to sleep with air conditioning on?

Yes. Set a temperature you find comfortable, keep the airflow off the bed and keep the filters clean. Some models have a sleep mode that raises the temperature gradually through the night.

Can I use a portable air conditioner in a bedroom instead?

You can, but portable units are noisy because the compressor sits in the room with you, and they need a hose out of a window. For a bedroom, a fixed system is far quieter. We explain why in do portable air conditioners work?

Do I need planning permission?

Usually not for a house in England, as long as the outdoor unit meets the size and noise limits. Flats and listed buildings follow different rules. See our planning permission guide.

What about a loft bedroom?

Loft rooms are often the hottest in the house and need a little more care with sizing and unit position. See our guide to loft conversion air conditioning.

Call 01772 288651 or use the form below to book a free survey. We will measure the room, recommend the right system and give you a clear written quote.

Last updated: November 2026.