How many decibels is a humidifier?
Humidifier decibel figures run from 16 dB to 45 on the makers' pages, but most makers rarely say what a figure describes. Across eighteen models:
Only one states a distance.
For the Superior Studio, Levoit puts its microphone 1.5 m away to get 19 to 45 dB.
None names a test standard.
Some give the quietest setting, some the loudest.
Levoit's NeoClassic 450 gives 21 dB in Sleep Mode. Winix gives 30 dB at the L201's highest speed. Levoit gives the Classic 160 under 28 dB at maximum mist.
Levoit alone prints a figure for 16 current US humidifiers, and our Levoit humidifier decibels page lists every one with the setting Levoit ties it to, from Sleep Mode to High Warm Mist.
Some give a bare number.
Dreo's 747S lists 21 dB, and Govee's H7140 24 dB, with no mode or distance.
So a figure for the loudest setting is worth more than the same number for the quietest. Between a Levoit and a Blueair, say, a few decibels apart can be no real difference at all.
Several big brands print no figure at all. We checked Vicks, Honeywell, Canopy, Pure Enrichment, Frida and Dyson. Their pages say "quiet" or "whisper quiet" without a number, so they are not in this guide.
Is an ultrasonic or evaporative humidifier quieter?
An ultrasonic mist humidifier has no fan and is close to silent, but an evaporative model on its low speed is the quieter long-term choice if you would rather not buy distilled water.
There are two broad types, and the quiet one has a catch.
Mist humidifiers (ultrasonic) break water into a fine mist. They have no fan, so they are close to silent, apart from bubbling or a pump starting. Against that, the EPA says ultrasonic and impeller humidifiers can release the minerals in tap water into the air, where some people notice a white dust on surfaces.
Evaporative humidifiers use a fan to blow air through a wet wick, filter or stack of discs. The EPA says evaporative and steam models are not expected to spread substantial amounts of minerals.
The catch here is the fan. Its noise changes with the speed: Levoit's Studio runs from 19 to 45 dB, and Venta's LW25 from 24 to 44 dB(A).
If you use a mist model, the EPA advises low-mineral water such as distilled water. If you would rather not buy water, an evaporative model on its low speed is the quieter long-term choice. Our evaporative humidifier guide compares wick and disc models figure by figure, with the daily output, wick cost and humidistat behavior of each.
Warm mist models heat the water. The EPA describes warm mist humidifiers as a type of steam humidifier and says to keep them out of the reach of children, because steam and boiling water may cause burns. What Levoit's warm mist manuals say about gurgling, warm-up time and Sleep Mode is in the adult bedroom section below.
How do you make a humidifier quieter at night?
To make a humidifier quieter at night, use the sleep setting, size up and run it low, and set a humidity target so it runs less.
Use the sleep setting. On many models it turns off the lights and drops to the lowest level. Levoit's NeoClassic 450 gives its 21 dB in Sleep Mode, and Venta says its sleep mode dims the display and switches to the lowest speed.
Size up and run it low. An evaporative model rated for a bigger room can run on a slower, quieter fan speed in yours.
If the room really is big, a living room or an open floor, our guide to the quietest humidifier for a large room shows how noise rises with output and reads the fine print on room coverage.
Set a humidity target. The CPSC suggests 30 to 50 percent, and the EPA says not to go above 50. A model with a humidistat or auto mode stops adding moisture once it gets there, so it runs less.
Watch the windows. The EPA says that if water condenses on windows, walls or pictures, you should move the humidifier, lower its setting, or use it less. If the room is damp to begin with, you need the opposite machine, and our guide to the quietest dehumidifiers covers the models with published figures.
What is the quietest humidifier for a bedroom?
The evaporative Levoit Superior Studio is our bedroom pick for homes with hard tap water, though Levoit's mist NeoClassic 450 prints 21 dB for its Sleep Mode.
A bedroom humidifier runs every night of the heating season, so read the figure for the setting it sits on after lights out. Two makers tie a plain dB figure to a named sleep mode: Levoit's image for the NeoClassic 450, "21 dB*" with "*While using Sleep Mode", and Dreo's "Sleep mode at 26dB" for the 735S. With no distance or test standard from either maker, the 5 dB between them is not a ranking, and the Levoit's own spec table now adds a 26 to 30dB row with no setting.
The NeoClassic is a mist model, though, so with hard tap water the evaporative Superior Studio stays our bedroom pick: rated for 600 sq ft, it can idle in a bedroom on the low fan speed Levoit rates for up to 40 hours.
The Dreo 747S lists 21 dB with no mode named, so it sits outside that comparison, though its 11 L tank is the largest here.
Warm mist suits an adult bedroom and not a nursery, and Levoit's manuals are the only documents we read that give a figure for the warm mist setting itself.
The OasisMist 450S manual lists its lowest level as under 26dB on Low Cool Mist and its highest as under 41dB on High Warm Mist; the LV600S manual gives under 28dB and under 40 dB for the same two settings. Those are ceilings for named settings, quoted here but not ranked against the Sleep Mode figures above.
Both manuals say "the heating element may make a gurgling noise if the water level is low" and that Sleep Mode switches warm mist off to reduce noise; the OasisMist manual adds that warm mist may take 15 minutes to arrive and that the nozzle can reach 140°F.
Neither Levoit is a pick here; among the picks, the Winix L201 offers warm mist, and its 30 dB at the highest speed is a ceiling for every lower setting.
Dry heated air empties a tank sooner: Dreo's FAQ says a humidifier runs out of water faster in a cold or dry environment, and Levoit's manuals say run time varies with room temperature and humidity, so treat the runtimes in our FAQ as best cases.
When the water does run out, Levoit's manuals describe a No Water indicator that blinks 10 times before the humidifier turns off, and Winix's an automatic shut-off; none describes a beep.
A humidity target changes the sound through the night: Winix's manual says the L201 cycles off at the set humidity and back on once the room falls 5 percent below it, while the NeoClassic 450's Sleep Mode holds one level. On lights, Winix's night light steps through 100, 50 and 20 percent to off, then the display light goes off too, and the OasisMist's Sleep Mode darkens its display.
How do you choose a quiet humidifier for a nursery?
A nursery humidifier is set at bedtime and left alone, so four things matter: the figure at the overnight setting, what stays lit, whether anything starts and stops by itself, and whether the tank reaches morning. Everything here comes from the makers' pages and manuals; we say nothing about an infant's health.
Levoit NeoClassic 450.
The one pick whose figure names its mode: a Levoit image pairs "21 dB*" with "Display Off Feature" and the note "*While using Sleep Mode". The page's spec table now lists 26 to 30dB with no mode named. Its night light is labelled "Blue Light-Safe", and the 4.2 L tank runs up to 42 hours on the lowest mist.
Levoit Classic 160.
A knob and, by Levoit's FAQ, no auto mode, so nothing changes until the dial turns. Levoit gives under 28 dB at maximum mist and "as low as 26dB and all lights off", with up to 25 hours at minimum mist.
Levoit Superior Studio.
Evaporative, with "no visible mist or spray" in Levoit's words and up to 40 hours with the fan on low, but no night light or dimming is described.
Blueair DreamWell Mini.
16 dB with no setting named, and 10 to 24 hours a fill. When the water runs low, Auto Wick Dry runs the fan "on fan speed 1 for 8 hours".
Dreo 747S.
The largest tank here, 11 L, rated for up to 100 hours. Its light is RGB, and Dreo says that once the target humidity is reached, Auto Mode stops adding moisture.
Auto modes change the sound on purpose. Levoit's Classic 300S manual says Auto Mode "will stop misting when the highest target humidity level is reached" and will "begin misting again" as humidity falls, and that "Sleep Mode changes the humidifier's mist setting to Auto Mode". A fixed low setting stays steady.
Two models outside the picks also fit. Levoit lists the NeoClassic 650 at 26 dB, with no mode named, and up to 62 hours from 6.2 L. Venta gives the LW15 Comfort Plus the same 24 / 34 / 44 dB(A) as the LW25, plus a sleep mode that "dims the display and switches the lowest speed".
On placement, Levoit's Classic 160 manual asks for "a hard, flat location for the humidifier at least 12 inches / 30 cm away from any walls", says "Mist should be directed away from walls, furniture, bedding, and appliances", and says "Keep the humidifier out of reach from children." It does not mention a crib.
Why is my humidifier so loud?
A humidifier gets louder when water is in the wrong place or a seal is loose, the makers' manuals say, and a pump starting or a switch turning on can make a brief sound.
Water in the wrong place.
Levoit's Classic 300S manual says a loud or unusual noise can be fixed by emptying the base, refilling the tank rather than the base, and seating the tank properly.
A loose seal.
The same manual says to check that the silicone sealing ring around the water valve is secure.
The pump.
Dreo says a brief, slight noise when its pump starts is normal.
The switch.
Levoit's Classic 160 manual notes a clicking sound when it turns on or off.
How often should you clean a humidifier?
The EPA advises emptying the tank, wiping surfaces dry and refilling portable humidifiers daily, and cleaning them every third day. The CPSC also suggests changing the water daily if possible, and unplugging the humidifier before you clean it. Follow the maker's own cleaning instructions first.
Which humidifier mistakes do buyers make most often?
The common humidifier buying mistakes are trusting "whisper quiet" without a number, comparing a quietest-setting figure with a loudest-setting one, using hard tap water in a mist model, skipping a humidity target and putting warm mist within a child's reach.
Trusting "whisper quiet" without a number
Several big brands use the phrase and publish no figure.
Check what the number describes.
Filling a mist model with hard tap water
The EPA says that is where white dust comes from.
Running it without a humidity target
The EPA says not to go above 50 percent.
Putting a warm mist model where a child can reach it
The EPA warns of burns.
