The Levoit Classic 300S is an ultrasonic humidifier meant for medium-sized spaces. It has a top-filling water tank with a usable capacity of 6.8 L (1.8 gal), a rotating mist nozzle, and Wi-Fi connectivity, allowing you to operate the unit remotely through the VeSync companion app, which also allows you to monitor ambient humidity levels or set operating schedules. There's also a separate tray to which you can add your favorite essential oil.
Our Verdict
The Levoit Classic 300S is decent for all-around home use. Its smart functionality essentially allows for nearly completely autonomous operation once you've inputted your desired humidity level and operating schedules. Combined with its near 40-hour max runtime, this unit requires minimal babysitting. Unfortunately, it can be a nuisance to clean. Its humidification capacity might be too low for efficient use in especially large spaces.
Long runtime.
Wide variety of smart features.
Can be a bit of a hassle to clean.
The Levoit Classic 300S is a very good option for use in bedrooms. It has a relatively compact footprint for a unit with this large of a water tank. A separate night mode turns off its display and night light and engages its automatic misting mode, which will attempt to meet the desired humidity level in your room. Combined with its extremely long runtime, you won't have to worry about changing settings or refilling the tank in the middle of the night. It's also very quiet and won't disturb you while you're resting.
Long runtime.
Wide variety of smart features.
Decent humidification capacity.
Quiet operation.
Can be a bit of a hassle to clean.
The Levoit Classic 300S is a bit of a pain to clean. There are quite a few parts that need periodic cleaning, none of which are dishwasher-safe. The top-fill water tank has a wide opening, but it can still be a bit of a hassle to reach every last nook and cranny. At the very least, everything that needs to be washed can be detached from the unit itself, so you can easily rinse and wash everything under a sink.
Can be a bit of a hassle to clean.
The Levoit Classic 300S provides decent humidification capacity. It isn't the most efficient option for adding moisture to large, open-concept areas, but it'll do fine in most living rooms or bedrooms.
Decent humidification capacity.
Not suitable for open-concept spaces.
The Levoit Classic 300S is quite energy-efficient. Its energy consumption is roughly on par with several other ultrasonic units on the market, though it doesn't output as much moisture as some of those peers.
Good overall efficiency.
Performance Usages
Changelog
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Updated Sep 25, 2026:
We've added a link to the Canopy Portable review in the Cleaning section to provide an alternative that's easier to clean.
- Updated Nov 22, 2024: Review published.
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Differences Between Sizes And Variants
The Levoit Classic 300S is only available in a single colorway: White/Blue. For those interested, here's the product label.
Let us know in the comments if you come across another variant of this humidifier.
Popular Humidifier Comparisons
The Levoit Classic 300S is a cool-mist ultrasonic humidifier. It shares a feature set similar to pricier smart devices like the Levoit LV600S. It has a built-in humidistat that allows for fully automatic operation and Wi-Fi connectivity, so you can run the device while you're away from home. Its humidification capacity is a little low, and this model is somewhat tedious to fully clean.
As a humidifier, the Levoit Classic 300S is far better than the Canopy Portable. The Levoit can be used to humidify an entire room, rather than a small area surrounding you. Beyond that, it has a far longer runtime than the Canopy, and features a built-in humidistat that automatically keeps humidity in your room at your desired level. Unlike the Canopy, you can also operate the Levoit using a smartphone. With all that said, the Canopy targets a different sort of use case, with a very compact design and rechargeable battery that allows you to run it far from a power outlet. It's also far easier to clean than the bulkier Levoit.
The Levoit Classic 300S is better than the Arctic Air Chill Zone. It has a much larger tank, a much longer runtime, a built-in humidistat, and app controls, making it far more practical for continuous or overnight use. The Chill Zone is smaller and puts out an impressive amount of moisture for its size, but its one-hour runtime is a real nuisance to keep refilling if you want to maintain humidity.
The Blueair InvisibleMist raises humidity more effectively than the Levoit Classic 300S. The Blueair relies on evaporative humidification, while the Levoit uses an ultrasonic system, though both come with a built-in humidistat, app support, and similar advertised room coverage. In our testing, the InvisibleMist made a bigger dent in humidity levels, so it's the better pick if a bigger jump in humidity matters most to you. The Levoit does last much longer between refills, though, thanks to a substantially larger tank.
The Levoit Superior Studio 450S is a better humidifier overall than the Levoit Classic 300S. The 450S uses a fan and wet wick to release moisture into the air, while the Classic 300S uses ultrasonic technology to produce a visible cool mist. The 450S can bring a dry room up to a comfortable humidity level faster, and you won't have to worry about white mineral dust settling on your furniture if you use tap water. It also takes less effort to clean, with several dishwasher-safe parts and a machine-washable wick. The Classic 300S lasts considerably longer between refills, though, which makes it the better choice if you want a humidifier that needs less frequent attention throughout the day; both offer app control and automatic humidity adjustment.
Test Results
The Levoit Classic 300S is a bit of a hassle to clean. Admittedly, it's better than Levoit LV600S in this respect, with marginally fewer parts you'll need to hand-wash. Unfortunately, none are dishwasher-safe. The water tank has a few tight spots that can be difficult to reach. At the very least, everything that needs washing can be detached from the unit. If you only need a personal humidifier for a small area around you and prioritize ease of cleaning, the Canopy Portable is worth a look, too.
The Levoit Classic 300. You can cycle between four different misting settings: Low, Medium, High, and Auto. In the Auto setting, the humidifier will vary its misting level on the fly to maintain an ambient humidity level between 40% and 50% by default.
There's also an integrated night light, which you can cycle through two levels of intensity.
The Sleep setting sets the humidifier to run in the 'Auto' misting mode and turns off the user display and night light.
You can also operate this unit using the Levoit VeSync companion app, which allows you to remotely manage the device or monitor ambient humidity levels in your home. The app also integrates with Amazon Alexa and Google Assistant, allowing you to change the humidifier's settings using only voice commands. You can also change the target humidity level the unit will aim for when set to its Auto mode.
It's a fairly efficient humidifier. It's more power-hungry than the Levoit LV600S when the latter is set to its cool mist setting, but it's still far from terrible in this regard.
This humidifier's overall efficiency is great. While your heating system might have to work a little harder in cooler months to maintain a comfortable temperature with the humidifier running constantly, this won't result in too big an increase.