Levoit Classic 300S humidifier review

With its large water tank, the Levoit Classic 300S humidifier quickly humidifies rooms up to 505 square feet and lasts up to 60 hours without a refill.

Image shows the Levoit Classic 300S humidifier and the mobile app against a white background.
(Image: © Amazon)

Live Science Verdict

Features like a smart-control app, an aromatherapy pad, and a night light make Levoit’s VeSync Classic 300S humidifier great for bedrooms or nurseries.


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    Auto mode automatically adjusts humidity level

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    Large water tank


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    Sensitive humidity monitor

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In this review, we’ll explain all of the features of the Levoit Classic 300S humidifier, including the usefulness of the VeSync app, how quickly each mist level humidifies a room, and how easy this humidifier is to fill and clean. 

Although not the most expensive model from Levoit, the VeSync Classic 300S humidifier is pricey (at $80 on Levoit’s website), but well worth the price if you’re looking for a humidifier with plenty of features and the ability to control the humidity level from another room. 

Levoit Classic 300S: Essential info

Smart control app controls the humidifier from any room

Water tank with 1.5 gallon/six-liter capacity

Effective range of 215-505 square feet

Built-in humidity sensor

Ability to set and maintain a humidity level

Aromatherapy essential oil diffuser


Up to 60 hours of run time

Auto mode

Night light

The Levoit Classic 300S is a smart, cool mist humidifier that connects to the VeSync app. The app works like a remote control, letting you turn the humidifier on and off, adjust the mist level, set a preferred humidity, and even control the humidifier via voice commands. If you allow the VeSync app to send notifications to your phone, it will also prompt you to clean your humidifier and tell you when the humidifier tank needs to be refilled.

Other features include a built-in humidity sensor, an aromatherapy pad where you can add a few drops of your favorite essential oils, a top-fill design that makes the tank easier to fill and clean, a night light with two intensity settings, and an auto-mode that automatically adjusts the humidity level of your room between 40 and 50 percent.

With its 1.5 gallons (6 liters) tank, the Levoit Classic 300S humidifier can humidify rooms from a range of 215 to 505 square feet for up to 60 hours without a refill.

Levoit Classic 300S review: How big is it?

  • Height: 13.4 (in) 
  • Depth: 7.5 (in) 
  • Width: 9 (in) 

The Levoit Classic 300S easily fits onto a dresser or counter, and may even sit on a wide window sill. Because this humidifier has a tall water tank, it isn’t easy to fill in shallow bathroom sinks. Although we tested this humidifier in a bedroom, we had to carry the tank to and from the kitchen to fill it. 

The size of your room is important to note when choosing a humidifier. This smart humidifier has a range of 215 to 505 square feet, making it great for small apartments or medium-to-large rooms. 

Image shows the Levoit Classic 300s on a white tabletop.

(Image credit: Future)

Levoit Classic 300S review: How easy is it to use?

The Levoit Classic 300S smart humidifier is easy to assemble. Out of the box, you simply need to fill the tank, put it onto the base, put the top back on, and plug it in. From there, the humidifier is ready to use with the buttons on the front, which allow you to set a mist level, turn on the night light, or set the humidifier to night mode. 

However, if you would like to use the VeSync app, you will need to download it from either Apple’s App Store or Google Play. The app is easy to download and to connect to your device. To connect, you hold the power button on the humidifier for 5 seconds until a WiFi symbol starts blinking in the upper-left corner of the display. Then, you choose your WiFi network and enter your password. Note that the humidifier only connects to 2.4 ghz networks — 5 ghz networks will not show up. 

Image shows the Levoit VeSync App.

(Image credit: Future)

Once you have the app downloaded and your device connected, you can switch the humidifier between manual, auto mode, or sleep mode via the app. On auto, you can set a target humidity preference, which turns the humidifier off when the built-in sensor reads 5 percent above and turns it back on when the sensor reads 5 percent below the target. Through the app, you can also turn the night light on and off, set a schedule to turn your humidifier on and off automatically, and set a timer to turn the humidifier off after a certain amount of time.

As with other humidifiers, the user guide for the Levoit Classic 300S suggests using purified or distilled water for the best air quality and performance. However, you can use water from your tap but watch for a white dust settling on the surfaces around your humidifier that indicates hard minerals. The user guide asks you to clean your humidifier with a white vinegar solution every week to avoid bacteria and mineral buildup. The VeSync app will alert you when it’s time to clean your humidifier.

Because this humidifier has a top-fill design, it’s slightly easier to clean and fill than humidifiers that require you to flip the tank upside down and unscrew a cap. Therefore, the Levoit Classic 300S may be a good option for older people or people who struggle with strength in their hands and arms. With a 1.5 gallon tank, however, the filled tank is still quite heavy to lift.

Levoit Classic 300S review: Performance

We tested the Levoit Classic 300S smart humidifier on all three mist levels, as well as the auto mode and other settings in the app. On the highest mist setting, the humidifier raised the humidity in a 234 square foot room from 60 percent to 65 percent within the first hour. By the second hour, the humidity had risen another 3 percent to 68 percent. By this time, the water tank was only about a quarter of the way empty. On the highest mist setting, the humidifier lasted 19 hours before needing to be refilled. 

At the middle mist level, the humidity of the same room rose from 57 percent to 61 percent within the first hour and increased another 5 percent to 66 percent by the second hour. At the lowest mist level, the humidity increased steadily at 1 percent per hour. It's worth noting all three mist levels were tested on already quite humid days. 

Our tester noted how quiet the Levoit Classic 300S humidifier is — you can barely hear it running even at the highest mist level. A decibel monitor registered 31 decibels at the highest mist level, but the background noise level even when the humidifier wasn’t running was about 27 decibels, effectively meaning this humidifier only added four decibels to the apartment’s noise. 

Image shows the Levoit Classic 300S humidifier at home on a white countertop

(Image credit: Future)

Both the four buttons on the humidifier display and the app are easy to understand and to use. The buttons on the display include a mist level button, a night light button, an on/off button, and a sleep mode button. The mist level button lets you cycle through the three mist levels as well as auto mode, which turns the humidifier on and off and adjusts the mist level automatically to maintain a humidity level of 40 to 50 percent. The night light button lets you turn the night light on and switch between two intensity levels. Finally, the sleep mode button turns the humidifier’s mist setting to auto mode and turns the display lights and the night light off. 

You’re able to change all of these settings in the app as well. The app also lets you set a humidity target outside of the 40 to 50 percent that auto mode achieves and gives you the option of setting the humidifier on a timer or a schedule. All of the options in the app are intuitive and easy to use. 

Levoit Classic 300S review: What’s good about it?

Image shows the Levoit Classic 300S humidifier aromatherapy pad

The Levoit 300S aromatherapy applicator (Image credit: Future)

The Levoit Classic 300S smart humidifier is an excellent option for many reasons. We like that it has a large water tank that can run for 19 hours on the highest mist setting, as well as the app that lets you change the humidifier’s settings from any room. 

This humidifier seems especially good for parents of small children, who may get a lot of benefit from the ability to set a humidity target and schedule the humidifier to turn on and off at a certain time of day. 

We also like the aromatherapy option on this humidifier. We added six drops of strongly-scented tea tree oil to the aroma pad and enjoyed the lightly-scented air in our room an hour later. Note that six drops is more than the recommended 2-3 drops. Our tester previously found that 2-3 drops used in the Levoit LV600HH's aroma pad didn’t spread the scent around the room. The effectiveness of the aroma pad may depend on how strongly scented your essential oil is, as well as how many drops you use. 

Levoit Classic 300S review: What’s not so good about it?

As with any other humidifier, the Levoit Classic 300S smart humidifier requires frequent cleaning. The user guide asks you to clean the tank and the base once a week. One benefit of the app is that it will notify you when it’s time to clean your humidifier, making sure you don’t forget. Although the top-fill design makes this humidifier slightly easier to clean, you’ll still have to let the water tank and the base soak in vinegar for 15-20 minutes and make sure all parts are dry before reassembling and using the humidifier again. However, you’ll find the same cleaning recommendations with other humidifiers. 

With so many features, the Levoit Classic 300S smart humidifier is a great choice for the price, but it is more expensive than many other humidifiers. If you don’t need all of the features, including the built-in humidity sensor, a cheaper and more basic humidifier might be a better choice. 

Finally, we found the built-in humidity sensor to be a bit too sensitive. The user guide asks that you place the humidifier at least 12 feet away from any walls to not overwhelm the humidity sensor. As that amount of space was not available in this tester’s apartment, we placed the humidifier on our bedroom dresser and tested the built-in humidity sensor against two other hygrometers. As expected, we noted a small but significant difference between the two (with the built-in sensor reading 71% humidity when the others read 69%, for instance). If you don’t have the space to keep the humidifier 12 feet away from any walls, the target humidity and auto mode settings may be off based on the built-in humidity monitor’s readings. 

Image shows the Levoit Classic 300S humidifier night light

(Image credit: Future)

Levoit Classic 300S review: User reviews

Amazon users rated this humidifier 4.6 out of five stars, with some of the top reviews praising it for being ultra-quiet, having an adjustable nozzle that can point in any direction, and having a wide opening at the top that makes it easy to stick your hand in for cleaning. 

One reviewer likes this humidifier especially for her asthma and allergies. The reviewer writes that this humidifier is very efficient and that they love being able to fill it from the top only every 2-3 days. 

We're in a 750 sq ft apartment. I have asthma and we both have allergies. We were using two typically sized humidifiers and a very small one on my bedside table. We ordered this humidifier, planning to replace one, but it's replaced two!

Amazon customer

Reviewers who weren’t as impressed with the Levoit Classic 300S smart humidifier struggled with the automated humidity levels, with one person saying that auto mode didn’t turn their humidifier on when the humidity was 45 percent but they had set it to a 65 percent target. Another person had the same issue as our tester, noting that the humidity sensor had a very different reading than a separate humidity monitor. Overall, it seems that you’ll need to put the humidifier far enough away from the wall for the auto mode to be accurate. 

Should you buy the Levoit Classic 300S?

The Levoit Classic 300S smart humidifier is an excellent choice if you want a humidifier that you can control remotely via an app and need to humidify a medium-to-large room or small apartment. It has a range of 215-505 square feet, a 1.5 gallon (six-liter) water tank, and an aromatherapy pad for essential oils. This humidifier lasts 19 hours without a refill on the highest mist setting and can last up to 60 hours on the lowest. Although this is a pricier option than other humidifiers, the many features and settings make it worth the cost. 

Kasandra Brabaw
Live Science Contributor

Kasandra Brabaw is a freelance science writer who covers space, health and psychology. She has a bachelor's degree in science and a bachelor's degree of arts from the University of Syracuse; she completed her master's of arts degree in journalism at Syracuse University in 2014. In addition to writing for Live Science and our sister site Space.com, Kasandra has written for Prevention, Women's Health, SELF and other health publications. She has also worked with academics to edit books written for popular audiences.