Levoit OasisMist 450S Smart Review

The 450S Smart is one of our favorite units for one simple reason — it's quite possibly the best at actually humidifying your space that we've seen through our years of testing at GearLab. It's solid in other areas as well, certainly, but if you want the most powerful model out there, this is your guy.

Humidification

The OasisMist is aptly named. If you want to visit the rainforests of Borneo on a budget, save the airfare; turn off the AC, pop on a recording of jungle sounds, and crank your OasisMist to full blast instead.

Starting at a balmy 40% relative humidity, we returned to our lab to find ourselves walking into a shocking nearly 60% humidity environment after an hour-long test. This model has some serious humidification power.

The secret is a dual technology platform: it has a sonication unit to vibrate water molecules into action, as well as a boiler unit to pump out copious amounts of steam. You can run either independently or together for some outrageous output. This is a model that we can confidently recommend for the larger rooms in a home, if you've had trouble with other units in the past.

Ease of Cleaning

As a prospective humidifier owner, you should resign yourself up front to a frequent cleaning of this (and any) unit. Every few runs of a full tank, ideally, to keep mold, mildew, and mineral scale at bay.

That said, the 450S makes this process fairly easy. We think cleanability is not fantastic, but still above average compared with our complete lineup. The top of the tank can be fully removed for easy scrubbing access, though squeezing between the wall and the vapor tower can get a little tight.

Cleaning of the base unit is where it gets a little annoying. There's a fair number of nooks and crannies to spend time on, which makes sense considering this is essentially two humidifiers in one, with the components to match. It's a worthwhile tradeoff for the flexibility and pure power you get, as far as we're concerned.

Noise

The OasisMist is technically on the louder end of what we've tested, but still hardly what we'd call 'loud'. At 43dB average noise level while running, it's similar to that of a forced air furnace, or the murmur of a quiet office. Enough to notice, but by no means excessive.

The boiler unit sounds nearly identical to a kettle coming to a boil; A pleasant rumble followed by a persistent hiss. The ultrasonic unit is more like a mild whine, but not an unpleasant tone. What most owners will notice is a consistent dripping sound as condensation builds. That can either be annoying or soothing, depending on the person.

Ease of Use

Much of this score is influenced by refilling the tank, which is by far the most interaction you'll have with the unit. The 450S follows the trend fully ingrained through the market, with an opening on top so it can be filled in place. If you do prefer a sink fill, there's also a large central handle on the tank, so no worries there.

The bad news here is that the reservoir capacity, while still on the larger side overall, is just not big enough to supply both Warm and Cool Mist modes when running together. 1.19gal (4.5L) empties fast on full blast; by our measure, under 20 hours. That obviously increases significantly with only 1 mode selected (over 31 hours on Cool Mist, for example).

We do really like the user interface, both on the unit itself, which has a large, bright display and a few key buttons, and the accompanying App. The App is worth a download in our opinion, to set schedules, sure, but also to unlock the excellent plant-focused feature set. The perfect relative humidity in your plant room can be calculated and automatically maintained by entering in the specific species you have!

Operating Cost

Something most of us probably gloss over in the decision on a purchase like this is considering the ongoing costs associated. A bit of electricity and water does add up after a while though. In this case, we estimate the average household will be on the hook for about $175/yr, assuming you run your humidifier 24/7 for 3 full months. That's a full 1/4 of the year.

A good chunk of that is electrical, actually, considering how much energy it takes to boil water (on the Warm Mist side). The other big piece of the puzzle is water — not tap water, but the treatment of that water. We figured buying demineralization tablets is a lot more affordable than having a constant supply of distilled water handy.

It's an unfortunate side effect of living in comfort (or giving your plants that comfort!), but it's better to know at the outset.

Should You Buy the Levoit OasisMist 450S Smart?

It's a refined, user-friendly product with some incredible humidification might. This model is for consumers who don't want to mess around and go for a compact unit that can deliver results even in larger spaces. The hands-off user should consider looking elsewhere, however, considering how often you'll be making trips to the sink.

What Other Humidifier Should You Consider?