Dreo HM512S vs Dreo HM713S
In short: The Dreo HM512S costs $20 less; the Dreo HM713S genuinely holds a larger room (781 sq ft against 185 sq ft); they are different mechanisms entirely — ultrasonic against hybrid; the Dreo HM512S costs about $74 less a year in wicks and watts.
| Spec | Dreo HM512S | Dreo HM713S |
|---|---|---|
| Approx. price | ~$70 | ~$90 |
| Type | Ultrasonic | Hybrid |
| Mist | cool | Warm and cool |
| Rated output | 0.75 gal/day | 3.17 gal/day |
| Output standard | Computed from the tank and the maker's longest runtime claim — the lowest setting | Maker's published output rate |
| Honest room size | 185 sq ft | 781 sq ft |
| Claimed coverage | 300 sq ft | 500 sq ft |
| Claim vs physics | 1.62× | 0.64× |
| Tank size | 1.32 gal | 1.59 gal |
| Runtime at the claimed room | 26 hr | 19 hr |
| Real runtime at full output | — | 12 hr |
| Yearly running cost | ~$7 | ~$81 |
| Replaceable media | None — nothing to buy | None — nothing to buy |
| White dust risk | Yes | Yes |
| Humidistat | Yes | Yes |
| Noise on low | 28 dB | 28 dB |
| Top fill | Yes | Yes |
| Dishwasher-safe tank | No | No |
| App control | Yes | Yes |
| Power | 26 W | 280 W |
Highlighted cells are the better number in that row, and only where a direction is unambiguous — more output and more supported room, less noise, cost and price. Honest room size and runtime are computed from each maker’s own published figures; here is the calculation.
Pros and cons
Dreo HM512S
- 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
- 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
Dreo HM713S
- One of the few ultrasonics whose published coverage claim is conservative against its own published output
- Warm mist and 3.17 gal/day capability in a unit that still fits on a side table
- Dual aroma pad tray, so oils stay out of the water
- Twelve hours of tank at full output, against the 60-hour low-setting claim
- The warm setting is what makes it expensive to run; cool mist costs roughly a tenth as much
- No demineralisation cartridge in the box; on hard water it is a $25.99 three-pack on top, changed every two months