The Vicks V3900 is a cool-misting evaporative humidifier. It's ultimately similar in design to the Vicks VEV400, as both units have bottom-filling water tanks with a usable capacity of 4.8L (1.3 gal), yielding similar max runtimes of approximately 30 hours. Both humidifiers are also intended for use in medium-sized rooms, with advertised coverages of 400 ft2. However, the V3900 differs from its stablemate with the addition of a UV bulb inside the tank to discourage bacterial buildup.
The Vicks V3900 is good for general home use. It's compact, easy to clean, and has a long runtime, so you won't have to worry about its tank running dry even if you leave it running all day. That said, the absence of any smart functionality means you'll have to monitor humidity levels yourself, and adjust the device's misting settings or even shut it off manually if too much moisture has been added to a room.
Long runtime.
UV sterilization system.
Compact size.
Easy to clean.
No automatic functionality.
Capacity is a little limited for especially large spaces.
The Vicks V3900 is a good option for use in bedrooms. It's small enough to be set up on a nightstand, yet has a high-capacity water tank that'll allow it to run overnight. You can use the humidifier with scented pads if you prefer, and its built-in UV sterilization system will help limit bacteria and mold growth in the tank. While it can get pretty noisy at higher fan speeds, it fades into the background at its lowest fan setting.
Long runtime.
UV sterilization system.
Compact size.
Easy to clean.
Quiet at low fan speed setting.
No automatic functionality.
Loud at highest fan speed setting.
The Vicks V3900 is impressively easy to clean. There are a few parts that need to be cleaned periodically, and not that many awkward spots that can't be easily reached with a brush, sponge, or washcloth. Better yet, unlike many other humidifiers in this price range, the V3900 also features a UV lightbulb to curb mold and bacterial growth inside the tank.
UV sterilization system.
Easy to clean.
The Vicks V3900 has a decent humidification capacity. It's well-suited for use in bedrooms and offices, but it might struggle to efficiently add moisture to especially big open-concept living spaces or apartments.
Capacity is a little limited for especially large spaces.
The Vicks V3900's efficiency is only reasonable. Its power consumption is rather high for a cool-mist unit, even more so for something with this level of humidification capacity.
Relatively low humidification efficiency.
The Vicks V3900 is only available in a single color variant: '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 so that we can update our review.
The Vicks V3900 is a basic evaporative humidifier. It has a remarkably long runtime and provides good overall humidification capacity, making it a good choice if you're shopping for a budget-friendly option. Still, it's worth noting that it can get pretty loud at its highest fan speed setting, especially compared to similarly-priced ultrasonic alternatives like the Crane Droplet.
The Vicks V3900 is very easy to clean. The humidifier comes apart pretty easily, and there are only three parts that need to be cleaned periodically. While none are dishwasher-safe, all of them can be detached from the base unit, so you can wash them in a sink under running water. Unlike the similarly designed Vicks VEV400, the V3900 also features a UV lightbulb to limit mold and bacterial growth inside the tank.
Unfortunately, it shares a common downside with the aforementioned VEV400 in that water can spill out of the back grille on the base unit if you tip it.
Ultimately, the Vicks V3900 is pretty basic. There are three misting levels that you can choose from by twisting the front dial. Unfortunately, it lacks a humidistat or even an auto-off function to shut the unit off once its tank runs dry.
Like many other Vicks humidifiers, you can add Vicks VapoPads for a scented mist.
This evaporative humidifier's efficiency is only okay. It consumes a little more power than the Vicks VEV400, which was already fairly power-hungry for a cool-misting unit.
The Vicks V3900's overall efficiency is great. Its cooling properties are great for use in warmer, drier environments, but it's worth noting that it can make your heating system work a little harder if you run it regularly in colder environments, leading to a slightly higher energy bill.