What the decibel figure tells you

The dB rating is how loud the machine is, measured by the maker. The scale is logarithmic, so a gap of a few decibels is a bigger difference to your ears than the numbers suggest. In our list the ratings run from 34dB to 46dB.

Makers don't always say how far from the machine they measured, or on which fan speed. Treat models a decibel or two apart as about the same, and check the listing or manual for the fan speed the figure applies to.

The rating also doesn't describe the kind of sound. A compressor model hums and clicks as the compressor switches on and off with the humidistat. A desiccant model has no compressor, so its sound is a steadier fan noise, and it gives off gentle warmth.

What to look for in a bedroom

  • A low rating on low fan. That is the setting it will run on overnight.
  • A sleep or night mode that turns off the display lights and holds the fan on low. A bright humidity readout can be harder to sleep through than the noise.
  • One size bigger than you need. A larger unit can keep a room dry on its low fan setting, where a small one would have to run flat out.
  • A tank that lasts the night, so it doesn't fill up and switch off in the middle of the night.
  • A timer, so you can run it in the evening and early morning and leave it off while you sleep.
Dehumidifier size calculator Choose 'One room' to find the size a bedroom needs, then pick the quietest model at that size.

Our picks

These are picked by their rated noise level, then by how well the rest of their specs suit a bedroom. We haven't tested them ourselves. See every model's rating in the noise and capacity table.

Quietest in our list

EcoAir DD1 Simple MK3

Type
Desiccant
Extraction
7.5 litres a day
Power
580W
Noise
34dB
Tank
2 litres
Cost per hour
15p
  • Laundry mode

The lowest noise rating we list, at 34dB, with 7.5 litres a day and a 2 litre tank. It costs 15p an hour to run. It is a desiccant model, so it also works in a cold bedroom, down to 1°C, but it costs more to run than a compressor model.

View on Amazon Manufacturer specs

For a small bedroom

MeacoDry ABC 10L

Type
Compressor
Extraction
10 litres a day
Power
198W
Noise
36dB
Tank
2.6 litres
Cost per hour
5.2p
  • Laundry mode

A 10 litre compressor model rated at 36dB. It is small and draws only 198W, which suits a single room you want to keep dry without much running cost.

View on Amazon Manufacturer specs

Running one overnight

Eight hours on the quietest model costs about £1.22. With the humidistat set to around 50 to 60%, it will cut back once the room is dry, so the real cost is often lower.

Costs use 26.32p per kWh, the Ofgem price cap, Direct Debit average for England, Scotland and Wales for 1 October to 31 December 2026. Your own tariff may differ. How we calculate.

You may not need it on at night at all. Running it in the bedroom with the door shut during the day, then switching it off at bedtime, keeps the room dry without any noise while you sleep. If the windows are still wet in the morning, see why windows get wet overnight.

Making any dehumidifier quieter

  • Stand it on a hard, level floor. On floorboards or an uneven surface the casing can vibrate and rattle.
  • Keep it a little way from walls and furniture, as the manual says. A blocked air inlet makes the fan work harder.
  • Put it across the room from the bed rather than beside it.
  • Clean the air filter when the manual says. A clogged filter adds fan noise.