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.
The room-size claim, reconciled
185 sq ft supported · box says 300 sq ft
The box says 300 sq ft. By the winter load calculation this output supports about 185 sq ft — the claim is 1.6× the room the machine can hold.
Holding 300 sq ft takes about 1.22 gal/day, which drains this 1.32-gallon tank in roughly 26 hr — against the 42 hours Dreo advertises, which is measured at the lowest setting.
What a year costs
No cartridge ships in the box. The demineralisation cartridge that fits it is a separate $25.99 three-pack, changed 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
- 5L top-fill tank
- Takes a demineralisation cartridge, sold separately
- Humidity sensor with target setting
- Dreo app and voice control
- Aroma tray
- 28 dB on low
Pros
- A litre more tank than the HM311S for $20 more
- Aroma tray sits outside the water path, so oils do not end up in the ultrasonic chamber
- Quiet enough for a nursery on its lowest setting
- Dreo's 300 sq ft rating is a modest stretch on its own tank and runtime figures, not a wild one
Cons
- The 300 sq ft figure implies about 26 hours of tank, against the 42 on the listing
- No demineralisation cartridge in the box; on hard water add a $25.99 three-pack, changed every two months
- Cool mist only, unlike the HM713S it otherwise closely resembles
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 HM512S 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 HM512S, head to head
Looked at alongside it
More from Dreo →
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.
195 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
Dreo
Dreo HM717S
Eight litres, warm and cool mist and a published 550 mL/hr - on paper the most complete portable in Dreo's line, though the demineralisation cartridge that would stop white dust is a separate purchase: $25.99 for three, or a $145.98 listing that bundles one against $119.99 without. The extra two litres over the HM713S buy about two and a half more hours at full output rather than the twenty the runtime figures suggest, because the 80-hour number is again the lowest setting. Where it genuinely earns the money is the middle: run it on auto in a 400 sq ft bedroom and it will go two or three nights between fills without a chilly mist.
860 sq ft supported · box says 600 sq ft