Reviews You Can Rely On

Dreo Smart HM311S Review

This unit defies the notion of affordability versus quality, impressing us with both its output and functionality, all while maintaining a budget-friendly price
gearlab tested logo
Dreo Smart HM311S Review
Credit: Matt Lighthart
Price:  $50 List
  • 1
  • 2
  • 3
  • 4
  • 5
Manufacturer:   Dreo
By Sentry Kelly and Ryan White  ⋅  Jun 12, 2024

#5 of 12
  • Effectiveness - 40% 7.0
  • Ease of Cleaning - 25% 7.0
  • Convenience - 20% 10.0
  • Run Time - 10% 6.9
  • Operation Cost - 5% 7.8

Our Verdict

The Dreo Smart HM311S has a premium feel with its high-end design and features, presenting a comprehensive array of smart functionalities in a compact form. With its intuitive display, responsive buttons, and app control, users gain access to a variety of features, including scheduling, voice control, cleaning reminders, timers, humidity data history, and a comprehensive maintenance guide with video tutorials. We particularly appreciated its simplicity and ease of use, with a standout feature being the light indicator that displays the room's humidity level. One potential drawback is that all features are accessible only through the app and not directly on the device itself. However, considering the price and capabilities of this humidifier, we believe this trade-off is justified. If you want to see just how capable the Dreo is, tap into our Best Humidifiers review.
Premium yet affordable
Smart features
Intuitive app
Requires app to access functions

Compare to Similar Products

dreo smart hm311s
This Product
Dreo Smart HM311S
Awards Best Buy Award     
Price $50 List
$49.99 at Amazon
$44 List
$43.99 at Amazon
$55 List$55 List
$59.99 at Amazon
$50 List
$29.97 at Amazon
Overall Score Sort Icon
Star Rating
  • 1
  • 2
  • 3
  • 4
  • 5
  • 1
  • 2
  • 3
  • 4
  • 5
  • 1
  • 2
  • 3
  • 4
  • 5
  • 1
  • 2
  • 3
  • 4
  • 5
  • 1
  • 2
  • 3
  • 4
  • 5
Bottom Line Affordable, feature-rich, and effective, this humidifier is a great all around choiceIt doesn't have the most power, but this device gets the job done at an affordable priceAdequate for small rooms, but there are better low cost/small room models availableThe design of these humidifiers is pleasing, but you might want more for your moneyThis model checks a lot of boxes, unfortunately it's core functionality isn't great
Rating Categories Dreo Smart HM311S Levoit Dual 150 Ult... Crane Drop Crane Adorables AquaOasis Cool Mist
Effectiveness (40%)
Ease of Cleaning (25%)
Convenience (20%)
Run Time (10%)
Operation Cost (5%)
Specs Dreo Smart HM311S Levoit Dual 150 Ult... Crane Drop Crane Adorables AquaOasis Cool Mist
Capacity 1.0 gal 0.8 gal 1.0 gal 1.0 gal 0.5 gal
Coverage Area 300 sq. ft. 290 sq. ft. 500 sq. ft. 500 sq. ft. 400 sq.ft.
Built in Humidistat Yes No No No No
Measured Noise (Low) 1.0 dBa .5 dBa .5 dBa .3 dBa 2.0 dBa
Measured Noise (Medium) 2 dBa 1 dBa 1 dBa 1 dBa 3 dBa
Measured Noise (High) 3 dBa 1 dBa 2 dBa 1 dBa 3 dBa
Nightlight Yes No No No No
Sleep Mode Yes No No No No
Available App Yes No No No No
Modes 1-3, Auto Dial Dial Dial 1-3
Relative Humidity Range 30-90 None None None None
Warm Mist No No No No No
Auto Shutoff Yes Yes Yes Yes Yes
Filter Required No Optional No No No
Aromatherapy Capable Yes Yes No No No
Removable Tank Yes Yes Yes Yes Yes
Top Fill / Bottom Fill Top Top Bottom Bottom Bottom
Humidification Technology Ultrasonic Ultrasonic Ultrasonic Ultrasonic Ultrasonic
Manufacturer Dimensions 10.2" x 11.0" x 5.5" 11.6" x 7.2" x 8.1" 13.4" x 8.6" x 8.6" 12.8" x 7.0" x 7.0" 10.0" x 4.0" x 5.0"
Weight 3.0 lbs 3.0 lbs 4.0 lbs 2.7 lbs 1.6 lbs
Run Time (High) 18 hr 29 hr 16 hr 21 hr 18 hr
Relative Humidity Change 1 hr 52.2% 41.8% 47.3% 33.2% 16.5%

Our Analysis and Test Results

In our comprehensive testing we were able to determine just how capable the Dreo HM311S truly is. We covered all the bases needed to properly assess each humidifier in order to help you make the best purchase decision for your needs. From effectiveness to operation costs, we got you covered. Spoiler alert, this is a rock solid appliance with top-tier capabilities. Keep reading on to find out how the Dreo performed across our testing.

Performance Comparison

The Dreo HM311S was put through the gauntlet, and it withstood every test we threw at it.
Credit: Matt Lighthart


The main function of these appliances is to humidify. This is why our core metric is effectiveness. Take away all the bells and whistles, and you're left with a simple device that serves a specific function, and that's to change the relative humidity in a given space. In order to accurately determine the output of each device, we ran them in a controlled 150 sq. ft. room to see how much they could elevate the humidity within the given time frame of 1 hour.

The Dreo HM311S managed to up the relative humidity by 52.2%. This is not exactly leading the pack in terms of pure output, but for the size and affordability, we found this to be a pretty great result. As long as you're not seeking the fastest humidity change possible, you'll be pleased with the Dreo. The proposed coverage area for this device is 300 sq. ft., and we have no doubt it'll hold its own in a room that is that size.

The indicator light lets you know the humidity level in the room.
Credit: Matt Lighthart

This model also offers the option to use scented oils for aromatherapy. During testing, we found the scent to be noticeable but not overly potent. Individual preferences may vary, but overall we believe most users will be satisfied with it. If you're considering purchasing an oil diffuser, this feature could save you money. Consider that the oil tray is an additional spot you'll need to maintain — more on that below.

dreo smart hm311s - there's a handy tray to handle all of your scented oils.
There's a handy tray to handle all of your scented oils.
Credit: Matt Lighthart

Ease of Cleaning

These devices can stockpile mold if not cleaned regularly. Therefore, it's crucial to choose a device that is easy to clean and maintain. To evaluate this aspect, we followed the manufacturer's cleaning instructions provided in the manual for each appliance. Some humidifiers require a little disassembly, including this one. However, we found it straightforward in practice.

The base of the Dreo HM311S is easily cleaned thanks to its removable float and rounded edges, providing convenient access. While its unique elongated oval shape enhances accessibility, it involves cleaning more pieces compared to other models, with some smaller components requiring a bit more effort to clean. However, overall accessibility remains high. Additionally, the top fill design streamlines the cleaning process for the main tank's interior. It's recommended to clean this humidifier once a month, and detailed instructional videos on how to do so are available on the app, which we found to be super helpful.

While there are a few extra pieces to deal with, the Dreo HM311S remains simple to maintain.
Credit: Matt Lighthart


In terms of convenience, we look for key features such as a built-in humidistat for self-regulation of output, smart app, a water tank light that can be toggled on/off, and the layout of controls for ease of operation.

The core functions of the Dreo HM311S are easily accessible through an intuitive display with responsive buttons, and it stands out as an all-in-one solution that offers everything needed for a seamless humidifying experience. One prominent feature is its color-changing light, indicating room humidity levels: yellow for dry (below 30%), green for ideal (31-60%), and blue for damp (above 61%). Surprisingly, this feature is missing in many pricier models. Additionally, the Dreo offers smart functionalities through its companion app, including maintenance reminders, timers, and humidity history.

dreo smart hm311s - the button interface is responsive and intuitive.
The button interface is responsive and intuitive.
Credit: Matt Lighthart

Run Time

This straightforward metric involves adding 50mL of water directly into the base (not the tank) of each appliance and then timing how long it would run before shutting off. This allowed us to calculate the total run time on a full tank. We tested this on every power setting available.

The float sensor in the tank of the Dreo HM311S detects the water level and disengages at around 125mL. When running on high, it will last an estimated 17.7 hours before requiring a refill. While it may not lead the pack in lasting power, it should more than suffice for most users, as depicted in the graph below.

Operation Cost

While not the most critical testing metric, it's essential to consider the overall operating cost of a new device, particularly if you're seeking efficiency without a hefty long-term expense. To assess this, we connected each humidifier to a Kilowatt meter to measure their power consumption across all available modes. Once that was done, we calculated our findings using the national average for cost/kwh.

The Dreo HM311S may not set any efficiency records, but it's a remarkably solid performer in this regard. Running it every day would cost an estimated $2.67 per month. However, since most users won't require continuous humidifier operation, the actual cost for running the Dreo is likely to be much lower. Nonetheless, it's reassuring to know that you could run it constantly if you need to and not incur a hefty cost.

dreo smart hm311s - testing the relative humidity changes on the dreo hm311s.
Testing the relative humidity changes on the Dreo HM311S.
Credit: Matt Lighthart

Should You Buy the Dreo Smart HM311S?

After extensive testing, we firmly believe that the Dreo HM311S is worth every penny. It's intuitive, unobtrusive, effective, and remarkably efficient and affordable. Moreover, it occupies minimal space in your home. If you've been searching for a straightforward humidifying companion that excels in nearly every aspect, this could be the perfect choice for you.

What Other Humidifiers Should You Consider?

If you're seeking maximum humidifying power, the Honeywell HUL430 delivers, albeit at a higher cost compared to the Dreo. For a balance of high output and ease of use, consider the Levoit Classic 300S Ultrasonic Smart. However, both options come with a higher price tag. If budget-friendliness is your priority, the Pure MistAire Ultrasonic or the Levoit Dual 150 Ultrasonic Cool are worth considering. While they may not match the performance of the Dreo, they offer more affordability.

Sentry Kelly and Ryan White