Dreo
Dreo HM311S
Fifty dollars buys the parts that usually cost more: a 4-litre top-fill tank, a real humidity sensor, app control and a 28 dB low setting. The demineralisation cartridge is the part to read carefully. The HM311S takes one, but the $49.99 listing does not include it - Dreo sells it as an $18.99 three-pack or in a $54.99 bundle - and without it the unit atomises whatever minerals are in the tap water, like any other ultrasonic. On the 300 sq ft Dreo prints, the arithmetic is tight rather than wrong: that room wants about 1.2 gallons a day, which would drain the tank in about 21 hours rather than the 32 advertised.
The room-size claim, reconciled
195 sq ft supported · box says 300 sq ft
The box says 300 sq ft. By the winter load calculation this output supports about 195 sq ft — the claim is 1.5× the room the machine can hold.
Holding 300 sq ft takes about 1.22 gal/day, which drains this 1.06-gallon tank in roughly 21 hr — against the 32 hours Dreo advertises, which is measured at the lowest setting.
What a year costs
No cartridge ships with the $49.99 listing. Dreo sells the demineralisation cartridge that fits it as an $18.99 three-pack, or a $54.99 bundle with one included, and the manual asks for a change every two months in season. Electricity assumes the rated 26 W for 12 hours a day across a 150-day heating season at 16¢ per kilowatt-hour.
Specifications
Maintenance profile
- Top fill
- Yes
- Replaceable media
- None — nothing to buy
- White dust risk
- Yes — atomises minerals with no demineralisation
Facts, not a score. Which of these matter depends entirely on whether the unit ends up somewhere you will actually clean it.
Features
- Takes Dreo's demineralisation cartridge, sold separately
- Top-fill 4L tank
- Humidity sensor and auto mode
- Dreo app with scheduling
- Aroma pad tray
- 28 dB on low
Pros
- Genuinely cheap for a unit with a real humidity sensor and app control
- Top filling and a tank shape wide enough to get a hand into for cleaning
- Takes a demineralisation cartridge for hard water, so the fix for white dust is an $18.99 accessory rather than a different humidifier
- Aroma pad tray outside the tank, so oils stay out of the ultrasonic chamber
Cons
- No demineralisation cartridge in the $49.99 box, so on hard tap water it leaves white dust until you buy one - roughly $24 a season at Dreo's change interval
- No warm mist, so in a cold bedroom the mist is noticeably chilly
- The app is another account and another device on the network for what is a $50 appliance
The pros and cons above are drawn from the maker’s documentation and published specifications. There is not yet a body of owner reports for this model that we have read.
What owners say
No owner discussion collected for the Dreo HM311S yet. The pros and cons above come from the maker's documentation and published reviews, and this section will fill in when there is enough first-hand material to summarise honestly. We would rather leave it empty than invent it — how we compare explains why.
Dreo HM311S, head to head
Looked at alongside it
More from Dreo →
Dreo
Dreo HM512S
A litre more tank than the HM311S, from the same playbook: humidity sensor, app, top fill and a 28 dB low setting. Dreo rates it for 300 sq ft, the same room as the smaller unit. That room calls for about 1.2 gallons a day, which would take the 5-litre tank down in roughly 26 hours against the 42 advertised - a modest stretch rather than a wild one. Neither Dreo ships a demineralisation cartridge in the box, and the 512S takes a different one from the 311S, sold as a $25.99 three-pack, so on hard water budget for it from the start. Against the HM311S the extra $20 buys a litre of water and not much else: both have an aroma pad tray, a sensor and the same app.
185 sq ft supported · box says 300 sq ft
Dreo
Dreo HM713S
Dreo publishes 500 mL/hr for this one, which is 3.17 gallons a day and puts it in the same real-output bracket as Levoit's LV600S at a slightly lower price. Like the Levoit, it makes white dust on hard tap water unless you add a demineralisation cartridge, which Dreo sells separately. The 500 sq ft claim is well inside what 3.17 gal/day actually supports - around 780 by the psychrometrics - making this one of the few portable ultrasonics whose room-size number is conservative rather than aspirational. The catch is the same as every hybrid: at the output that justifies the claim, the 6-litre tank is empty in about twelve hours.
781 sq ft supported · box says 500 sq ft
Vicks declines to put a square-foot number on this one, describing it only as a medium-room unit - which, given how the rest of the category behaves, is its own kind of honesty. A 4.5-litre tank running 30 hours works out to just under a gallon a day, the same ballpark as everything else at this price. Dual scent-pad slots, a variable output dial, no filter. The usual ultrasonic caveats apply and the tank neck is narrow enough that cleaning it properly means a bottle brush.
234 sq ft supported