Disclaimer: As an Amazon Associate I earn from qualifying purchases. It may also contain other affiliate links. Read our affiliate disclosure.

Levoit Classic 300S Ultrasonic Smart Humidifier Review

Our Overall Rating:
Humidification Performance
Ease of Cleaning
Noise Level
Build Quality

Learn how we test & rate here.


Top-Fill Convenience & App-Enabled — These standout features make it my go-to choice among many humidifiers.


  • Quiet operation.

  • A specific sleep mode is included.

  • Easy to use.

  • Diffusion function is included.


  • The humidistat is not very accurate.


256 ml/h (our test result)







# We earn a commission if you make a purchase, at no additional cost to you.


This ultrasonic humidifier comes with a filter, a bonus for its type. The top-fill design and app control are user-friendly, and the 256ml/h output makes it ideal for larger rooms. It's quiet, with an aroma tray and sleep mode adding a nice touch. It's already impressive, but a more accurate humidistat could enhance it further.

Why you can trust this review: I purchased this Levoit classic 300s humidifier with our own money, took pictures, and spent two weeks testing it for its noise level, output, and humidification performance.

Levoit has established itself as a prominent player in the humidifier industry, with many of its models gaining popularity.

Among them, the Levoit Classic 300s is marketed as a humidifier suitable for large rooms. But does it truly have the power to effectively humidify sizable spaces such as living rooms? And does it offer any standout features? Let’s delve into this review to find out.

Levoit Classic 300S Humidifier Ratings Breakdown

Humidification Performance 10?

levoit classic 300s humidifier output compare

Manufacturers often exaggerate the coverage of humidifiers, but with the Levoit Classic 300s boasting a sizable 6L water tank, I expected it to offer commendable humidification performance.

While it’s not always the case, in my experience, humidifiers with larger water tanks tend to deliver higher output.

After conducting a one-hour test, I was pleasantly surprised to find that the Classic 300s could produce an impressive output of up to 256 ml. This result indicates its suitability for larger spaces.

According to our calculations, it can effectively humidify an area of 277 sq. ft., increasing the humidity from 35% to 50% within 3 hours. If you’re willing to let it run for 10 hours, it can cover an even larger area of 340 sq. ft.

Two other models we tested, the Vornado EVDC500 and Homedics Total Comfort Warm & Cool Mist, offer similar output levels, but they come with larger water tanks.

It is perfect to fit a smaller space as well because the mist level is adjustable and it has a built-in humidistat.

Ease Of Cleaning 9?

levoit classic 300s humidifier-ease of cleaning

Thanks to its top-fill feature, the water tank boasts a large opening on the top, with the mist tube situated on the side. I can easily insert my whole hand and remove any debris from the water with a damp cloth.

Unlike many ultrasonic humidifiers from other brands, this model has a filter in the water. However, I found it easy to remove by turning the filter housing counterclockwise. The noise silencer is also removable.

Cleaning the base is also straightforward, and the float is easily removable. According to the instructions, it is advisable to soak the silencer, float, and filter in a vinegar-water mixture when cleaning.

In summary, while this model requires cleaning of the filter, it is a simple task. Additionally, the filter is inexpensive to replace, so if it becomes filled with particles, you can easily swap it out for a new one.

Noise Level 10?

ModeSound Level(dB)

This humidifier operates quietly, regardless of the level I choose. Even when placed by my bedside, the noise is minimal.

At just 36 dB (high mode), the noise level is quite low, even compared to other ultrasonic humidifiers I have tested.

On the high level setting, I did notice some faint humming noise from the motor, but it was barely noticeable, only audible when I placed my ear close to the machine.

Compared to the noise produced by the Vicks filter-free model I’ve tested, this humidifier is much quieter.

Overall, I don’t believe it would disturb anyone’s sleep, even for a light sleeper.

Usability 9.5?

Compared to many single-knob models I have tested, this classic 300s comes many advanced features. However, it doesn’t mean that it is difficult to use.

There are four buttons on the front for turning on and off the machine, and adjusting the mist level, sleep mode, nightlight. Basically, by using these four buttons, it is engough for daily use.

Many people these days are accustomed to controlling everything from Alexa or their phone. This humidifier can do just that.

I have tried connect it with the vesync app. It is very straightforward so that I can set the target humidity level, set the timer or choose my plant that is going to be watering by this humidifier.

The whole process is smooth. I think the app is easy to use too.

However, I noticed that the humidistat is not very accurate.

I believe this discrepancy arises because the ultrasonic humidifier creates a more humid environment directly around the machine, and the sensor can only measure the humidity level within this immediate vicinity.

As a result, the humidistat tends to show a higher reading compared to the number from my hygrometer.

Therefore, if you want it to maintain a humidity level of 50%, you may need to set the humidistat to around 60%.

Build Quality 10?

levoit classic 300s humidifier - build quality

Levoit humidifiers are typically cost-effective. I previously reviewed the Levoit Dual 200s model, which boasted many great features at a low price point.

The Classic 300s model, however, comes with a slightly higher price tag. However, considering it has a larger tank, the price is fair. It still doesn’t fall into the expensive category.

Every part of this machine is made with sturdy plastic. Even small components like the filter housing or the nozzle have smooth edges, ensuring safety during handling. The walls of the water tank are thick, giving me confidence when carrying it.

Warranty 9?

Generally speaking, most ultrasonic humidifiers only offer a one-year warranty. However, in line with other Levoit humidifiers, this model has a 2-year warranty, which is great.

Design and Sizing

levoit classic 300s humidifier design
Mist ModeAuto, Low, Med, High
ColorBlue; Grey
Size9.6"D x 7.5"W x 13.4"H
Tank Size6L
Weight4.3 lbs

While this humidifier boasts a 6L water tank, it doesn’t have a large footprint. It’s slightly taller than smaller models.

It comes in two colors: blue and grey. I opted for the grey one, but I think both colors to be unobtrusive when placed in the home.

The water tank features two handles on the side for easy carrying, along with a max water level mark for convenience. The tank cover can be easily lifted by dragging the nozzle, and the nightlight is located on the bottom of the water tank.

levoit classic 300s humidifier max water line

Inside the base, there’s no special design, just a straightforward setup. On the back of the base, there’s an aroma box that can be pulled out to add a few drops of essential oil.

On the front, you’ll find four buttons for control, along with an LED display that shows the humidity level, timer, mist level or reminds you to add water.


Price Range: $$$$$

Electricity Cost: $15.72 per year (365*8 hours on high mode)

Extra cost: Filter and Aroma Pad Replacement (they are extremely cheap)

This mid-range humidifier offers excellent value with its array of features.

Unlike most ultrasonic humidifiers, this one incurs ongoing costs. You’ll need to replace the filter and aroma pad periodically. However, their prices are extremely low, so it shouldn’t be burdensome.

The package includes an aroma pad replacement and two filter replacements, which should last for some time.

Given that it’s a cool mist humidifier, it consumes low wattage. On high mode, it uses around 23.4W, while on low, it’s only 14.3W, resulting in minimal impact on your electricity bill.

What Set This Levoit Classic 300S Humidifier Apart?

It is a smart humidifier.

Levoit is a humidifier brand known for embracing smart features in its products. You can find many smart humidifier models from this brand.

The Levoit 300s model works quite well with its VeSync app. I felt that the manufacturer has put a lot of effort into developing this app so that every function can be easily controlled and it’s easy to connect.

This humidifier has an auto mode. I was able to adjust the target humidity level on the app so it can stop working or start working at any humidity level I want. I also found that when the automatic stop is off, it will continue to work at a low level.

Many people like to use humidifiers for plants, and the manufacturer has noticed. In the app, there’s a special plant program so it can water the plant according to the schedule I set.

I enjoy changing the settings from the app while lying in bed before sleeping. I find it convenient, especially since I prefer placing the humidifier on the table rather than the bedside table.

With this feature, I can save effort by adjusting the settings without needing to get up and walk over to the humidifier.

It has a top-fill feature.

levoit classic 300s top fill

This is a convenient feature, especially considering the large water tank.

Imagine if the opening were at the bottom; you would have to flip the large water tank upside down after refilling, which could be cumbersome, especially for those with weak hands.

It’s understandable why more and more models in the market are adopting this design.

Another advantage is that it helps prevent water spillage from the base. When the opening is at the bottom of the water tank, lifting it often results in some water dripping onto the table.

It is a filtered ultrasonic humidifier.

levoit classic 300s filter

Most ultrasonic humidifiers are filterless, but not this one. The sponge filter in the water tank could be helpful when filling it with tap water because it can filter out some mineral particles or dust.

However, its effect is not as effective as the wick filter in evaporative models, and it can’t entirely prevent the formation of white dust. Nevertheless, the water filter in this model is much cheaper than the wick filter.

While the machine could continue to work without this filter, using it is definitely beneficial.

Most Levoit ultrasonic models have included this type of filter.

It has a sleep mode.

While I’m not a light sleeper, I still prefer sleeping in an environment that is completely dark. This humidifier has a specific sleep mode that can turn off all the nightlights and LED displays at once to ensure sleep is not disturbed.

This might seem like a standard feature for a humidifier, but it’s not. Many models I’ve tested have indicator lights on the knob that can’t be turned off. For example, the Vicks Filter Free and Bear 5L humidifiers both have indicator lights on the knob.

Some models even have nightlights that can’t be turned off. For instance, the Vornado EVDC500 model has lights on each side that can’t be turned off.

Therefore, this sleep mode could be useful for many people who prioritize a dark sleeping environment.

Other humidifiers to consider

When considering alternatives to the Levoit 300s humidifier, I’ve chosen two models suitable for large rooms. One can produce warm mist, while the other is an evaporative model.

For Cheaper Price

Vornado EVDC500 Energy Smart Evaporative Humidifier

This humidifier, while having a similar output to the Levoit 300s, is an evaporative model. It might produce more noise and the light can't be turned off completely. However, its wick filter can effectively filter out most impurities in the water, preventing the white dust issue. Plus, the machine is even easier to maintain.

Read Full Review

View on AmazonView on Vornado

# We earn a commission if you make a purchase, at no additional cost to you.

Vornado EVDC500 Energy Smart Evaporative Humidifier review

For Smaller Size

LEVOIT LV600HH/S Smart Warm and Cool Mist Humidifier

This is another popular humidifier from Levoit. It boasts a larger output and can produce both warm mist and cool mist. While it operates quietly, it's a bit more challenging to clean due to its additional parts.

View on AmazonView on Vesync

# We earn a commission if you make a purchase, at no additional cost to you.

LEVOIT LV600HH:S Smart Warm and Cool Mist Humidifier review

Who Should Buy This Humidifier? 

LEVOIT 300S Ultrasonic Smart Humidifier

View on AmazonView on Vesync

# We earn a commission if you make a purchase, at no additional cost to you.

LEVOIT classic 300S Ultrasonic Smart Humidifier review

Having tested numerous humidifiers, this one stands out as one of my favorites.

Firstly, its high output makes it an excellent choice for those seeking to improve humidity levels in larger rooms.

Its top-fill feature and easy controls make it ideal for individuals with weaker hands, such as the elderly.

Moreover, its dedicated app, which allows for plant watering scheduling, makes it a great option for plant enthusiasts.

Its quiet operation and ability to completely turn off the night light in sleep mode will appeal to light sleepers.

While it may not be the most budget-friendly option, its multitude of excellent features make it a great value overall.

If you have any questions about buying a humidifier, feel free to shoot me an email at [email protected] or leave a comment below!

Avatar photo

Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested more than 150 products in person, including humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

Leave a Comment

Table Of Content