Millilitres an hour, and what they leave on the furniture · review
Levoit Classic 300S review
Levoit's top model in this comparison: a 6 L ultrasonic top-fill humidifier with a built-in humidity sensor that drives an automatic mode, a touch-operated LED display, app control through VeSync, and Alexa/Google Assistant voice control. Levoit states up to 60 hours of runtime, coverage up to 47 m², and 26 dB in sleep mode with the display dimmable.
The bottom line The most feature-complete humidifier in this comparison — the largest tank, the longest runtime, and the only one with app and voice control layered on top of a genuine humidity sensor. It's priced accordingly and, like the other ultrasonic models here, still carries the hard-water white-dust caveat that only the evaporative Philips in this line-up avoids.
The largest tank in this comparison
At 6 L, the Classic 300S holds more than double the water of the Dreo reviewed alongside it and well over double the Levoit Classic 160’s 2.5 L. Levoit states up to 60 hours of runtime and coverage up to 47 m², both the highest published figures among the four humidifiers we compared in this family. The trade-off is size and weight — a 6 L tank is heavier to carry and refill than the smaller units here, even with the top-fill design that lets water go in without removing the tank.
A humidity sensor with an actual display
This is the closest thing to a true hygrostat among the four models in this comparison. Levoit describes a built-in humidity sensor that monitors the room and automatically adjusts mist output, paired with a touch-operated LED display on the unit itself — a genuine step up from the Dreo’s undocumented sensor and the Levoit Classic 160’s plain manual dial. One caveat: the listing we checked does not state the adjustable target range in numeric terms, so we can’t publish a specific percentage figure the auto mode holds to, only that Levoit describes the behavior as automatic and sensor-driven.
App and voice control
Where the other three humidifiers in this comparison are purely manual or on-device, the Classic 300S adds Levoit’s VeSync app and voice control through Alexa and Google Assistant. The app requires a 2.4 GHz Wi-Fi connection specifically — Levoit’s own listing notes that 5 GHz-only networks aren’t supported, worth checking before buying if your home network doesn’t broadcast a 2.4 GHz band.
Noise and the same ultrasonic caveat
Levoit publishes 26 dB for sleep mode, with the display dimmable or switchable off entirely for night use, and states a mist height of at least 60 cm. It’s worth repeating, though, that the Classic 300S is still an ultrasonic humidifier under the smart features: the same hard-water, white-mineral-dust characteristic that applies to the Dreo and Levoit Classic 160 in this comparison applies here too. A sensor and a display do not change the underlying mist technology.
Where we found it in stock
We checked Amazon.de, Amazon.fr, Amazon.it, Amazon.es, Amazon.com, and Amazon.co.uk. ASIN B0B5G5L4PS carried a live offer on DE, FR, IT, and ES, with prices from about 80 € (FR/IT/ES) to about 90 € (DE). On Amazon.com and Amazon.co.uk the ASIN exists with a product page and images but had no live offer — no price, no seller — at the time we checked, so we’re not listing it as currently available there.
Bottom line
Of the four humidifiers in this family comparison, the Classic 300S is the one built for a larger room and a household that wants app and voice control layered on top of genuine sensor-driven humidity adjustment. It’s the most expensive to buy but not by a wide margin over the Philips, and it holds meaningfully more water than either ultrasonic alternative here.
Prices quoted in this text were read on 2026-08-24. The live price is at the top of the page.
Where this one sits in its aisle
At 80 €, it is the 3 cheapest of the 4 models in this category published here.
Cheapest in the aisle30 €
Median80 €
Dearest in the aisle90 €
What we like, and what we don't
Strengths
6 L tank is the largest in this comparison, backing Levoit's stated 60-hour runtime — the longest between refills of the four humidifiers
Humidity sensor plus an on-device LED display is the closest to a true hygrostat among the models we compared — it monitors and auto-adjusts rather than requiring a manual guess
VeSync app and Alexa/Google Assistant support let it be scheduled or checked on remotely, a feature none of the other three models here publish
26 dB sleep mode with a fully dimmable display keeps it usable in a bedroom overnight
Compromises
Levoit does not publish a specific mist ml/h output figure for this model in the listing we checked, unlike the Dreo and Philips reviewed alongside it
Requires a 2.4 GHz Wi-Fi network for app control; 5 GHz-only home networks are not supported
As an ultrasonic model, hard tap water carries the same white-mineral-dust risk described for the other ultrasonic units in this comparison — the sensor and display don't change the underlying technology
Listed on Amazon.com and Amazon.co.uk with a product page, but had no live offer on either at the time we checked
Specifications
Technology
Ultrasonic, cool mist
Tank
6 L, top-fill
Coverage
Up to 47 m², per Levoit
Runtime
Up to 60 hours, per Levoit
Noise
26 dB in sleep mode, per Levoit; mist height at least 60 cm
Humidity control
Built-in humidity sensor drives an automatic mode; touch-operated LED display, dimmable or off for sleep
Connectivity
VeSync app (2.4 GHz Wi-Fi only, 5 GHz not supported); Alexa and Google Assistant voice control
Mist output
Not published in this listing
Extras
Timer, night light, aroma-oil compartment separate from the water tank
Amazon reference
B0B5G5L4PS (live offer confirmed on DE, FR, IT, ES; listed but with no live offer on US or GB at check time)
Questions people actually ask
Does the Classic 300S automatically maintain a set humidity level?
Levoit describes a built-in humidity sensor that monitors the room in real time and automatically adjusts mist output to keep humidity at a suitable level, controlled through the touch panel, the VeSync app, or voice assistants. The listing does not publish the exact adjustable target range, so we're reporting the auto-mode behavior as described rather than a specific percentage figure.
Can it be controlled with a phone or voice assistant?
Yes — Levoit publishes VeSync app control (over 2.4 GHz Wi-Fi only) plus Alexa and Google Assistant compatibility, which none of the other three humidifiers in this comparison offer.
Is it available everywhere we checked?
We found a live offer on Amazon.de, Amazon.fr, Amazon.it, and Amazon.es. The ASIN has a product page on Amazon.com and Amazon.co.uk but no active seller offer on either at the time we checked, so US and UK buyers would currently land on a listing without a price.
Our score
8.7/ 10
The most feature-complete humidifier in this comparison — the largest tank, the longest runtime, and the only one with app and voice control layered on top of a genuine humidity sensor. It's priced accordingly and, like the other ultrasonic models here, still carries the hard-water white-dust caveat that only the evaporative Philips in this line-up avoids.
Who this one is for
A larger bedroom or shared space where app/voice control, a long refill interval, and sensor-driven auto humidity matter more than the lowest possible price.
Compared with its closest rivals
Same category, nearest prices. Only the specifications every one of them states are shown — a half-empty column compares nothing.
250 ml/h ultrasonic cool mist · 3 L top-fill tank · 26 dB sleep mode
Dreo rates this ultrasonic cool-mist humidifier at 250 ml/h from a 3 L top-fill tank, with a 360° nozzle reaching up to 40 inches, a stated 26 dB in sleep mode, up to 30 hours of runtime, adjustable ambient light, and a separate aroma-pad tray for essential oils. Dreo's listing also names a built-in humidity sensor, though it does not describe a numeric auto-target mode tied to that sensor.
Best for: A bedroom or nursery where a quiet overnight runtime and a large refillable tank matter more than app control or a numeric humidity display.
2.5 L tank · 23 dB · up to 25 h runtime, lowest setting
Levoit's entry-level ultrasonic humidifier, rated at 23 dB with a 2.5 L top-fill tank covering up to 20 m² and up to 25 hours of runtime on the lowest mist setting. Mist volume is controlled with a manual dial and a 360° nozzle; there is no humidity sensor, digital display, or auto mode published for this model.
Best for: A small bedroom or a second humidifier for a child's room, where a low purchase price and simple manual control matter more than smart features.
Philips' Series 2000 evaporative humidifier uses NanoCloud technology — a wick-based natural-evaporation process rather than an ultrasonic disc — rated at 200 ml/h from a 2 L tank, covering up to 32 m², at a stated 33 dB. Philips publishes 3 humidity levels plus a sensor-driven auto mode and a sleep mode, and states the evaporative process does not disperse the mineral dust associated with ultrasonic humidifiers.
Best for: A household in a hard-water area, or anyone who wants to avoid ultrasonic mineral dust specifically, and is willing to pay more and refill more often for that.
