The Quietest Air Conditioners

If you are fitting air conditioning in a bedroom, nursery or home office, noise matters as much as cooling power. The quietest modern wall units are close to silent on a low setting. The catch is that the figure in the brochure is only part of the story.

The Quietest Indoor Units

These are the lowest published indoor noise ratings for wall-mounted ranges from some of the brands we install. All are sound pressure figures, measured on the unit's lowest fan or quiet setting.

• Mitsubishi Electric MSZ-LN: 19 dB(A) on the lowest fan setting (2.5 and 3.5 kW models).

• Mitsubishi Electric MSZ-AP: 19 dB(A) on the lowest fan setting (2.5 to 5.0 kW models).

• Panasonic Etherea: 19 dB(A) in quiet mode (2.0 to 3.5 kW models) and 30 dB(A) for the 5.0 kW model.

• Toshiba Haori: 19 dB(A) in quiet mode (2.5 and 3.5 kW models).

Fujitsu, LG and Samsung also make quiet wall units, and we can give you the figures for any model you are considering.

What the Figures Mean

• dB(A) is a measure of sound adjusted to the way the human ear hears it.

• Every 10 dB sounds roughly twice as loud. A unit at 29 dB(A) sounds about twice as loud as one at 19 dB(A).

• The headline figure is the quietest setting. Toshiba rates its Haori 2.5 kW unit at 19 dB(A) in quiet mode and 41 dB(A) on high, so the fan speed makes a big difference.

• Sound pressure and sound power are different. Sound pressure, usually measured 1 metre from the unit, is close to what you hear. Sound power is a higher number used for engineering calculations, so make sure you are comparing like with like.

For context, the World Health Organization recommends keeping continuous background noise in a bedroom below 30 dB(A) for good sleep. A correctly sized unit on a low setting sits well within that.

Do Not Forget the Outdoor Unit

The outdoor unit holds the compressor and the main fan, so it is louder than the indoor unit. For example, the outdoor unit for the Mitsubishi Electric MSZ-LN25 is rated at 46 dB(A) in cooling and 49 dB(A) in heating. Toshiba quotes 37 dB(A) for the Haori's outdoor unit in silent mode.

Outdoor units installed under permitted development in England must meet the MCS 020(a) noise standard, which sets a limit of 42 dB(A) at the nearest window of a neighbouring home. Where the unit goes matters as much as which model you choose. Our planning permission guide explains the rules.

How We Keep a System Quiet

• Correct sizing. A unit sized for the room can run on a low fan speed most of the time. An undersized unit runs flat out and is louder.

• Careful siting. We put the outdoor unit where it will disturb you and your neighbours least, away from bedroom windows where possible.

• Solid mounting. Brackets and ground stands with anti-vibration mounts stop vibration travelling into the building.

• Night and quiet modes. Many models can lower indoor and outdoor noise at night. On the Mitsubishi Electric MSZ-LN, night mode reduces outdoor unit noise by 3 dB.

• Regular servicing. Clean filters and coils let the fans move air easily. A dirty unit works harder and gets louder. See our servicing page.

Are Portable Air Conditioners Quiet?

No. A portable unit has its compressor inside the room. Testing by the consumer group CHOICE found portable units running at 57 to 74 dB(A) on a high setting. Even the quietest are much louder than a fixed wall unit. We explain more in do portable air conditioners work?

Frequently Asked Questions

What is the quietest air conditioner?

Of the ranges above, the Mitsubishi Electric MSZ-LN and MSZ-AP, Panasonic Etherea and Toshiba Haori are all rated at 19 dB(A) on their quietest setting. The best choice for your room depends on its size, the look you want and your budget. For bedrooms, see our guide to bedroom air conditioning.

Is 19 dB(A) silent?

Not quite, but it is very quiet, around the level of rustling leaves. In a quiet bedroom at night, you may just hear the air moving.

Why is my air conditioner louder than it used to be?

Blocked filters, a dirty coil, a worn fan bearing or loose mountings can all increase noise. A service usually finds the cause. See top signs your AC system needs repair.

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.