Dreo HM311 Humidifier 4L
- 4L tank, up to 36 hours per fill
- 28 dB operating noise
- Mist up to 40 inches tall from a 4-inch outlet
- 5 micron ultrafine mist
- Top fill design
- Aroma and ambient light, oils not included
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A quiet top fill cool mist humidifier for a bedroom or nursery that runs through the night on one tank. Room coverage, power draw and output rate are not listed.
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ASIN: B0CNRC4G2CModel: HM311Category: Humidifiers
Overview
Bedrooms and nurseries are the setting for this ultrasonic cool mist humidifier, which runs quietly through the night on a single tank. Water pours in from the top, and a dual intake pushes a tall mist column into the room.
Low noise and long runtime suit overnight use beside a bed or crib. The listing gives no room coverage or mist output rate, and ultrasonic units can leave white dust with hard tap water.
Who it's for
Dry winter bedrooms, nurseries and home offices suit a quiet unit that refills from the top. People wanting warm mist, or a rated coverage area for a large living room, should look at other models.
Pros and cons
- Quiet enough for sleep
- Long runtime per fill
- Top fill, no tank flipping
- Tall mist column spreads moisture
- Room coverage not listed
- Cool mist only
- Essential oils not included
- Output rate unstated
Performance notes
An ultrasonic plate vibrates water into a fine mist, which is quiet because there is no boiling or loud fan. A tall mist column helps moisture spread before it settles. Hard tap water can leave mineral dust nearby.
Specifications
| Brand | Dreo |
|---|---|
| Model | HM311 |
| Capacity & performance | |
| Capacity | 4 liters |
| Noise | 28 dB |
| Construction & materials | |
| Color | Ebony |
| Other details | |
| Runtime | Up to 36 hours |
| Operation Mode | Ultrasonic cool mist |
| Room Type | Bedroom |
| Other Special Features Of The Product | Top fill, 4-inch mist outlet, mist up to 40 inches, 5 micron mist, aroma, ambient light |
Frequently asked questions
Is the DREO HM311 a warm mist humidifier?
No. It is an ultrasonic cool mist humidifier with no warm mist mode listed.
How long does the DREO HM311 run on one tank?
The 4L tank provides up to 36 hours of moisture.
Can I use essential oils in the DREO HM311?
Yes, it supports aromatherapy, but essential oils are not included.
How loud is the DREO HM311?
It runs at 28 dB.