DREO HM311S 4L Humidifier – Hands-on Review!

Full Review

The DREO 311S is one of the most attractive humidifiers I’ve tested. Its central ambient light reflects off the water and creates a calming effect.

It reminded me of looking into a softly lit aquarium.

I used the DREO 311S for some time and put it through the same testing process as the other models we’ve reviewed.

The DREO 311S is a compact humidifier designed for rooms up to 300 sq. ft. (28 m²), making it well suited to bedrooms, living rooms, and similar spaces.

How We Tested the DREO 311S?

1. We test every humidifier in the same 194 sq. ft. (18 m²) room. Before each test, we use a dehumidifier to lower the relative humidity in the room to around 40% RH, so every unit starts the test under identical conditions.

2. To track humidity levels, we use the Govee Hygrometer H5075 as our primary measuring device. We also set up a ThermoPro hygrometer as a secondary unit, which we use to confirm and cross-check the readings from the Govee.

3. We turn the DREO 311S to maximum speed and let it run for 60 minutes. During this time, we measure the total RH increase the unit achieves, as well as how long it takes to raise the humidity by +5% RH.

4. We measure how much water the DREO 311S uses in 60 minutes of running at max speed. Based on the measured water consumption (in mL/h) and the tank capacity, we calculate the real runtime on a full tank, not the manufacturer’s claim, but what we actually measured in our test.

5. Finally, we measure the power consumption of the DREO 311S using a power meter. From this, we calculate how much it would add to your electricity bill if you ran it 24/7 at max speed for a month, and its efficiency in mL of water per watt-hour (mL/Wh), a metric that shows how well the unit converts electricity into moisture output.

In addition to using the humidifier regularly, we measured its performance with the Govee Hygrometer H5075. Subjective impressions were not included in the performance score.

This test helps us compare its humidification performance and efficiency with similar models.

It also shows how closely the measured results match the manufacturer’s claims.

Efficiency Test

In the first test, we used a dehumidifier to lower the humidity in a room of 194 sq. ft. (18 m²) down to around 40%. After that, we placed the DREO 311S in the room and let it run for 60 minutes at max speed.

We measured humidity using the Govee Hygrometer H5075, our reference device for testing and comparing humidifiers.

Over 60 minutes of operation at max speed (high mode), the DREO 311S raised the relative humidity by 12 percentage points, from 40.7% to 52.7%. This is a solid result, though not quite in the top tier. It took 18 minutes to raise the humidity by 5 percentage points.

For comparison, the Homvana H101 raised humidity by 5 percentage points in 16 minutes, but its overall test result was somewhat weaker, increasing humidity by around 10.8% under similar conditions.

However, if we compare the DREO 311S to the Levoit OasisMist 450S, we see what a true class leader looks like: the Levoit raised humidity by 16.9 percentage points under identical conditions.

Overall, it performed slightly better than several similarly sized models, although it remained behind the strongest performers.

Runtime

We also measured the tank capacity and water-consumption rate and compared the results with competing models.

One of the DREO 311S’s main advantages is its 4-litre tank, which provides a long runtime when used across different mist settings.

However, on max speed, the DREO 311S consumes about 206 mL per hour, meaning it will use up all the water in the tank in 19.4 hours at this speed.

The runtime is impressive, although the relatively low moisture output contributed to weaker humidification performance than I expected. I also like the extended mist outlet, which appears to spread mist across a wider area.

If you look at the chart, you’ll see that the DREO 311S ranks somewhere in the middle, but also that its tank can last a very long time.

For comparison, the Levoit Dual 150 consumes about 150 mL of water per hour on max speed, and on a full tank it will last around 19.1 hours.

Overall, the large tank provides excellent runtime, particularly at lower mist settings.

The DREO 311S is rated at just 26W, so its electricity costs are relatively low.

This means that if you ran the DREO 311S on max speed, 24 hours a day, for a month, your electricity bill would increase by about $2.18, and on the lowest speed it would increase by about $1.37.

For comparison, the Levoit Classic 300S, which is somewhat more powerful than the DREO, would cost you around $2.01 on max speed and $1.23 on the lowest speed.

In terms of moisture output per watt-hour, the DREO ranks below several comparable models. The DREO produces 8.3 mL/Wh, which is lower than the output of several comparable models.

All in all, humidifiers generally aren’t expensive to run and aren’t major consumers of electricity, but I think the DREO could have been optimized a bit better.

Cleaning & Maintenance

When it comes to cleaning and maintenance, every humidifier requires maintenance and occasional cleaning. Tap water can cause stubborn limescale to build up on the plastic components. Tap water can also increase the amount of white mineral dust released into the room.

The DREO 311S is easy to disassemble and clean. A soft cloth should be sufficient for most surfaces.

I wouldn’t recommend washing the device’s parts in a dishwasher, as this can cause warping and damage to the plastic.

Features Overview

For a humidifier in this category, the DREO 311S offers an unusually broad range of features, including app control, an informative display, a night light, and voice-assistant support.

Humidity Sensor

The DREO 311S uses what DREO calls a ‘smart humidistat.’ It’s a built-in sensor for precise humidity measurement and automatic adjustment.

According to DREO, the sensor and its algorithm measure humidity with twice the precision of standard sensors.

This sensor works in combination with other features on the device. It displays the current humidity level on the screen, adjusts the night light, and also controls the auto mode feature.

Auto Mode

Auto mode is an advanced feature that lets you fully automate your DREO humidifier.

When set to auto mode, the DREO will adjust its speed based on the target you’ve set and the current humidity level in your space.

For example, if you set the target to 60%, the DREO will run at a higher speed until it reaches that target, then it will slow down and maintain humidity at 60%.

Auto mode reduces manual adjustments while helping manage water and energy use.

Aromatherapy

I already mentioned earlier in the review that I don’t recommend pouring essential oils directly into the device.

DREO instead provides an aroma pad on the rear of the unit, allowing essential oils to be dispersed without adding them to the water tank.

While not as efficient as diffusers, I think this is a really useful feature that many people will love.

Smart App

The DREO smart app unlocks plenty of advanced features. The app is a valuable addition, particularly for remote control, scheduling, and humidity tracking.

There are also various other features, such as advanced scheduling and setting up voice control for Google Assistant and Amazon Alexa.

Schedule & Timer

These are very useful features that let you automate the operation of the DREO 311S humidifier.

Scheduling lets you set when you want the DREO to turn on or off, while the timer lets you set how long you want your humidifier to run before it shuts off automatically.

What’s different about setting up these functions is that the timer can be set directly on the device, while scheduling can only be set through the app.

Warranty

DREO offers a 12-month warranty on this model.

Design & Build Quality

The DREO 311S is one of the best-looking humidifiers I’ve tested. Its most unique design elements are the night light and elongated mist outlet.

The device is made from high-quality plastic, and the build quality is very good. The top houses the water tank, while the base at the bottom holds the multifunctional control panel.

On the back of the device is the air inlet, while mist is released from the top. The aroma pad opening is also located on the back.

The display provides several useful status indicators. It shows ‘LO’ when the humidity is below 10% and ‘HI’ when it exceeds 90%. When the water level is low, the tank indicator flashes for five seconds before the humidifier enters standby mode.

What comes with the device?

When you buy the DREO H311S humidifier, along with the device you also get a user manual, quick start guide, cleaning guide, cleaning brush, and two aroma pads.

FAQ on DREO 311S