Dreo
Dreo HM717S
Eight litres, warm and cool mist, a published 500 mL/hr, and a demineralisation cartridge - on paper the most complete portable in Dreo's line. The extra two litres over the HM713S buy about four 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 or a dusty dresser.
The room-size claim, reconciled
781 sq ft supported · box says 600 sq ft
The 600 sq ft on the box is what the winter load calculation supports for this output — one of 18 units here whose claim lands within 5% of its own published rate.
Holding 600 sq ft takes about 2.44 gal/day, which drains this 2.11-gallon tank in roughly 21 hr — against the 80 hours Dreo advertises, which is measured at the lowest setting.
What a year costs
demineralisation cartridge three-pack around $18, changed every two months in season. Electricity assumes the rated 300 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
- Demineralisation cartridge
Facts, not a score. Which of these matter depends entirely on whether the unit ends up somewhere you will actually clean it.
Features
- 8L top-fill tank
- 500 mL/hr published output
- Warm and cool mist
- Demineralisation cartridge included
- Humidity sensor and auto mode
- Dreo app and voice control
- 28 dB on low
Pros
- The refill interval at realistic settings is the genuine benefit, and it is large
- Warm mist, real output figure and demineralisation in one unit - not a combination on offer at this price elsewhere
- At the middle settings the published output and tank size work out to two or three nights between fills in a 400 sq ft room
Cons
- Eight litres is heavy and the unit is large enough to be furniture
- Sixteen hours at the full output, not the 80 advertised
- Warm mode draws 300W, so the cheap-to-run case only holds if you never use the feature you paid for
- New enough that long-term reliability reports are thin
What owners say
Summarised from owner discussions and long-form owner reviews. Nobody here has used this unit.
This is the unit owners reach for when noise is the deciding constraint. The comparison they make explicitly is against the big evaporative consoles: those move more water but have a fan you can hear across a room, and this one does not. Owners describe hearing it faintly on high and not at all on medium or low.
The refill figures owners give are genuinely good — around two days in a shared living space, up to five in a closed bedroom — because in practice it runs on auto rather than flat out. The demineralisation cartridge is the answer to hard water and the reason this sits in the no-white-dust filter; owners on well water who skip it get the residue anyway.
The one recurring worry worth knowing is a smell complaint: at least one owner reports a Dreo unit developing a persistent odour that days of careful cleaning and drying did not fix. It is not a universal report, but it is specific enough to check for early while a return is still possible.
What owners like
- Owners consistently name it as very quiet even on its highest setting, which is the specific reason people pick it over a console evaporative
- Real-world refill intervals are long: owners report roughly two days in an open living room and up to five in a closed bedroom
- The app, auto mode and shut-off-at-target all get used rather than ignored, and the nightlight can be turned off
- No required filter, with a demineralisation cartridge available for hard water
- Owners with apartments split across two ends buy two of these rather than one large unit, because the noise floor makes that practical
Common complaints
- Owners on well or hard water report that running it without the cartridge produces the usual mineral residue, and the cartridges are an ongoing cost
- At least one owner reports a persistent smell from a Dreo unit that survived days of thorough cleaning and drying, and could not be resolved
- Eight litres of water is heavy and the unit is large enough to count as furniture
- The 600 sq ft figure is the usual optimism — the tank would not sustain that room for a day at the required output
Questions owners ask
How quiet is it really?
How often will I fill eight litres?
Do I need the demineralisation cartridge?
What about reports of a smell?
Dreo HM717S, head to head
Looked at alongside it
More from Dreo →
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. It also keeps the demineralisation cartridge, so unlike the Levoit it can run tap water without decorating the room. The 550 sq ft claim is close to 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 550 sq ft
Dreo
Dreo HM512S
A litre more tank than the HM311S and a bigger room-size claim, from the same playbook: demineralisation cartridge in the box, humidity sensor, app, top fill. The 500 sq ft on the listing is the least defensible number Dreo publishes - that room calls for about 2 gallons a day, which would take the 5-litre tank down in roughly 16 hours against the 42 advertised. Treat it as a 250-300 sq ft machine and it is a good one. Against the HM311S it buys a litre of water and an aroma tray for $25; against Levoit's Classic 300S at a similar price it buys the demineralisation cartridge Levoit charges extra for, and gives up the longer-established app.
185 sq ft supported · box says 500 sq ft
Dreo
Dreo HM311S
Dreo does the thing most ultrasonic makers leave to a separate accessory listing: it ships a demineralisation cartridge and tells you when to change it. That single decision is why the HM311S sits in the no-white-dust filter on this site while several pricier ultrasonics do not. The rest is a competent $50 bedroom unit - 4-litre top-fill tank, real humidity sensor, app, 28 dB. Independent testing found it better suited to rooms under about 200 square feet than the 300 on the box, which is roughly where the arithmetic lands too: 300 sq ft wants 1.2 gallons a day and would drain the tank in about 21 hours rather than 32.
195 sq ft supported · box says 300 sq ft