Are Dreo humidifiers quiet? Their pages say 21 to 32 dB

Which Dreo humidifier is the quietest?

The 747S, at 21 dB from Dreo's lab at the lowest mist setting. The other five picks fall between 26 and 30 dB.

All six were in stock on dreo.com and on Amazon on November 8, 2026.

Eleven more current models with a figure

No photo footnote was opened for these eleven, so the setting behind each figure stays unnamed.

Every footnote names the bottom of the dial

Each footnote read for this page credits "DREO lab" and names the quietest way to run the unit. The wording drifts from page to page: "lowest mist setting" on the 747S and 755S, "lowest mist level" on the 735S, "the lowest setting" on the HM524, "the lowest cool mist level" on the HM717S and "Sleep Mode" on the HM311. All six point at the same end of the range, so they are treated here as one group.

What is missing is a distance from the humidifier, or any test standard.

A figure taken a foot away and one taken across a room can differ a lot. That is why a Dreo figure can only be set against another Dreo figure, as our piece on comparing decibel ratings explains.

Sound pressure on the newer 311

Only the second generation Humidifier 311 carries the label "Noise (Sound Pressure)". For other products the label matters, since sound power and sound pressure can differ by 10 dB or more. Dreo does not say how its other figures were taken, so there is no telling whether they would carry the same label in practice.

Why is my Dreo HM311 so loud?

Most likely because it is running above Sleep Mode, where its 28 dB was taken. Turning the mist down comes first in Dreo's advice, and moving it off carpet second.

The full answer on the HM311 page reads: "1. Set the mist level to a lower setting. 2. Please do not place the humidifier directly on the carpet, as this will easily lead to clogging of the humidifier air inlet holes. 3. The humidifier may malfunction." For that last case it gives support@dreo.com.

On the HM717S and HM713S pages the same list gains a step at the top: "Turn down the humidification level or adjust to sleep mode to effectively reduce noise."

Two products are called 311

The original HM311 is the one Amazon sells under that model number, and its box list reads "1x Dreo HM311 Humidifier". Dreo's support address for the hm311 opens a different page, though, for "Humidifier 311 (2nd. Gen)", model DR-HHM021, a newer product listed at 21dB and sold out on November 8. Check which one you own before reading a manual or comparing figures.

Why does a Dreo tower humidifier make a pumping noise?

The large towers, 747S, 735S and 755S, pump water up from the tank. A short, slight sound when the pump starts is normal, according to Dreo's FAQ for each.

"If the noise is very loud, please contact the support team," the 735S page adds. That start-up sound is no part of the decibel figure, which describes steady running at the lowest mist setting.

The evaporative 774S has a pump too, and on startup it "expels air or scale buildup from the pipe to prevent blockage, causing a louder noise that will disappear after 5 seconds."

A bigger tank is not always louder

Size and figure only partly track each other. The 16 L 755S lists 30 dB against 21 dB for the 11 L 747S, under identical footnote wording, yet the 11 L 735S sits at 26 and the 4 L HM311 at 28. The 747S holds 11 liters and still has the lowest figure in the range.

What the 755S gives up for its extra 5 liters is 9 dB. A 10 dB step is heard as roughly twice as loud, so that gap comes close to doubling, though without a distance the comparison stays an estimate.

For rooms above about 500 square feet, set Dreo against other makers in our large room humidifier guide.

Warm mist has no figure

The HM717S figure is footnoted to the lowest cool mist level. Neither it nor the HM713S or 813S prints a number for warm mist.

There is a reason to expect a difference. The HM713S table lists "Rated Power: 26W (Cool), 280W (Warm)" and mist output of "300ml/h (cool mist), 500ml/h (warm mist)": warm mode heats water and pushes out more mist. If warm mist matters to you, take the 28 dB as a cool mist figure only.

Is the Dreo 774S evaporative humidifier quiet?

Not by its figure. The 774S lists 32dB, the highest on any current Dreo humidifier, and names no fan speed, so it cannot join the group of footnoted mist figures.

It is a different kind of machine, too. An evaporative humidifier blows air through a wet wick, and most of its sound comes from that fan, where an ultrasonic model makes little more than a trickle. The 774S runs up to 50 hours from 10 liters, and for noise Dreo's FAQ suggests "Set a lower mist level". To weigh it against other wick models, see our evaporative humidifier list.

Three models print no figure or disagree with themselves

The 409S and the newer 311S print no noise figure on dreo.com. "Quiet" appears among the 409S's special features with no number beside it, and the 311S, a 4 liter model, lists only mist output and tank size. Neither is ranked.

The 306S gives 26 dB in its table and 28dB in its description, so both numbers are quoted and the model is ranked nowhere. A milder mismatch sits on the 735S, whose text ties its 26 dB to Sleep Mode while the photo footnote says lowest mist level.

How Dreo's figures line up with Levoit's

Loosely, since neither brand gives a distance. Levoit's lowest Sleep Mode figure, 21 dB on the NeoClassic 450, is level with the Dreo 747S.

The habits differ. Levoit often writes its figures as ceilings, "under 26dB", and ties some to a named setting in its manuals, while Dreo prints a plain number and footnotes it on a photo. Our Levoit humidifier page groups those figures setting by setting. Dreo's fans show yet another pattern, a near-identical figure on many towers, covered in Dreo fan decibels.

All of these numbers sit near the bottom of the decibel chart. For a pick across every brand, see the quietest humidifiers.