DREO HM311 Humidifier 4L
- Floor Area: 300 sq ft
- Capacity: 1.1 gallons
- Runtime: 36 hours
- Operation Mode: Ultrasonic
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A straightforward 4L ultrasonic humidifier built for quiet, long overnight runs, with a strong ratings history behind the HM311 name even without review text attached to this listing.
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ASIN: B0CCY6VG8ZModel: HM311Category: Humidifiers
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Overview
Dreo's HM311 (DR-HHM001) is a 4-liter ultrasonic humidifier built for long overnight runs, rated for up to 36 hours per fill at 28dB with a top-fill tank and a rotating mist nozzle.
Where the brand's newer 4L model leans on app and Auto control, the HM311 is the simpler, quieter workhorse in the same tank size, with the pitch resting on runtime and noise level rather than smart features.
- 4L tank rated for up to 36 hours
- 28dB quiet operation
- Up to 40 inch mist projection
- Modular parts for easier cleaning
Who it's for
Works for a bedroom or nursery where a long, quiet overnight run matters more than app control. Not the pick for someone who specifically wants smartphone or voice control, since the emphasis here is on the tank and mist mechanics rather than connectivity.
Pros and cons
- 36-hour runtime from a 4L top-fill tank
- Rated as low as 28dB for overnight use
- Top-fill design skips flipping the tank
- Doubles as an aromatherapy diffuser
- No app or voice control described
- No review text attached to this listing yet
Performance notes
Ultrasonic atomization keeps operating noise down to a stated 28dB, and the dual-intake design with a 4 inch outlet is what produces the tall, up to 40 inch mist plume. High-frequency atomization breaks the output into a 5 micron ultrafine mist meant to spread through a room rather than settle wet on nearby surfaces.
Specifications
| Brand | Dreo |
|---|---|
| Model | HM311 |
| Dimensions & fit | |
| Item Weight | 3.1 pounds |
| Item Dimensions D X W X H | 5.5 × 11 × 10.2 inches |
| Capacity & performance | |
| Capacity | 1.1 gallons |
| Power & efficiency | |
| Wattage | 26 watts |
| Voltage | 120 volts |
| Power Source | Corded Electric |
| Construction & materials | |
| Material | Plastic |
| Color | White |
| Included components | |
| Number Of Packs | 2 |
| Unit Count | 1 |
| Other details | |
| Floor Area | 300 sq ft |
| Runtime | 36 hours |
| Operation Mode | Ultrasonic |
| Filter Type | Pre Filter |
| Control Type | Touch |
| Item Shape | Oval |
| Part Number | DR-HHM001 |
| Item Type Name | Humidifier |
| Room Type | Bedroom, Kids Room, Living Room, Nursery, Office |
Frequently asked questions
What is the difference between the Dreo HM311 and Dreo's other 4L humidifier?
The HM311 (DR-HHM001) focuses on quiet, long runtime and a tall mist plume, while Dreo's other 4L model adds app-based Auto humidity control.
How long can the HM311 run without a refill?
Dreo rates the 4L tank for up to 36 hours of continuous runtime.
Is the tank easy to fill and clean?
It uses a top-fill design so you do not need to flip the tank, and Dreo describes the parts as modular for easier removal when cleaning.