Vicks humidifiers
Vicks has 4 units here, from $40 to $60, across 3 types. The most capable is the Vicks Warm Mist Humidifier V745A at 2 gal/day, enough for 493 sq ft. 2 of the 4 cannot produce white dust.
Across the lineup, Vicks's published room sizes average 1.5× what the output supports, so treat the square footage on the carton as a ceiling rather than a rating. How that is calculated.

A boiler with a tank on it, and the oldest idea in the category. Steam humidifiers have no ultrasonic disc to scale, no wick to replace and no fan to hear - the water boils, minerals stay in the pot, and what leaves the machine is distilled by definition. That is why the V745A shows up in so many nursery and sick-room recommendations despite being unchanged for well over a decade. It is also 260 watts of a hot electrode boiling water in a room with a child in it, twelve hours to a tank, and an appliance you descale rather than rinse. The 250 sq ft on the box is the most conservative figure Vicks publishes; two gallons a day would hold nearly twice that.
493 sq ft supported · box says 250 sq ft

Where the VUL545 atomises, this one evaporates - a wick, a fan and a UV lamp in the reservoir. For anyone who bought a Vicks ultrasonic and then found white powder on the dresser, the V3900 is the same brand's answer, and it is the cheaper half of the answer compared with Honeywell's HCM-350. A gallon a day against a 400 sq ft claim overstates by about 60%, which is mild by the standards of this category. The wick is the ongoing cost and the reason some owners drift back to filter-free units.
246 sq ft supported · box says 400 sq ft

Vicks declines to put a square-foot number on this one, describing it only as a medium-room unit - which, given how the rest of the category behaves, is its own kind of honesty. A 4.5-litre tank running 30 hours works out to just under a gallon a day, the same ballpark as everything else at this price. Dual scent-pad slots, a variable output dial, no filter. The usual ultrasonic caveats apply and the tank neck is narrow enough that cleaning it properly means a bottle brush.
234 sq ft supported

Vicks sells more humidifiers through drugstore shelves than most of this catalog sells anywhere, and the VUL545 is the one people pick up at nine in the evening when a child has croup. It works: a gallon of water, visible cool mist, a scent pad slot for menthol, and no filter to have forgotten to buy. What it will not do is hold 400 square feet - that room wants about 1.6 gallons a day, four times what the advertised 36-hour run delivers - and on hard water it powders dark surfaces within a few days.
165 sq ft supported · box says 400 sq ft