Nursery humidifiers, by noise and cleaning burden

A tower with a 1.47-gallon tank, a demineralisation cartridge in the box, and a 426 sq ft claim - an oddly specific number that at least suggests somebody calculated rather than rounded up to 500. HoMedics now lists it as the Decor Series Large Humidifier, and its box gives the CMTF91 a 17-18 dBA noise figure, which with the cartridge makes it one of the quiet, dust-free units here. Seventy hours on the lowest setting is among the longest here, which as usual means the lowest setting moves very little water: about half a gallon a day. Where it earns its place is the combination of a demineralisation cartridge and a real humidistat at $100, which most rivals at this price do not offer.

One 1.38-gallon top-fill tank, warm and cool mist, a demineralisation cartridge in the box, a humidistat and an eighty-five-hour low-setting claim - one of the longest numbers in this catalog, and the one that best illustrates why the number is nearly meaningless. Eighty-five hours from 1.38 gallons is 0.39 gallons a day, about a fifth of what the 521 sq ft printed alongside it would require. HoMedics also prints 21-23 dBA for it, which with the cartridge puts it among the quiet, dust-free units here, and adds an eight-hour auto-off timer.

Eight watts at full speed, no wick and no filter - Venta's disc-stack airwasher costs a great deal up front and almost nothing to run, which is the whole argument for it. Its manual is also the only one in this catalog that states the assumption behind its room-size figure: "listed square feet are based on 8-foot ceilings". That single sentence is more transparency than the rest of the category manages combined. What Venta will not tell you is how much water it actually moves - no output rate appears in the manual or on the product page - so the 485 sq ft figure has nothing behind it that a buyer can check.

The LW25's larger sibling: a 3-gallon basin, the same disc stack and eight watts at full speed, sold for 645 sq ft. Like the LW25 it comes with no output rate - not on Venta's product page and not in the LW15/LW25/LW45 manual - so the 645 sq ft has nothing behind it a buyer can check; the three gallons a day some retailers quote belongs to the older Venta Original LW45. Venta has since moved on: its US store shows both colours out of stock and names the AH550/AH555 Original Connect as the newer model. No wick, a two-year limited warranty, and a basin you will have your hands in every couple of weeks.

A Swiss design-led cube that has been on sale, essentially unchanged, for over a decade - which in a category full of two-year model cycles is its own recommendation. Output is a published 1.9 gallons a day against a 540 sq ft claim; the load calculation supports about 470, so it overstates by fifteen percent, which is modest for this category. The tank is only 0.9 gallons, which at full output is about eleven hours. Eighteen watts at most, a real hygrostat, and a cube small enough to sit on a bookshelf.

This is what happens when Levoit stops building ultrasonics. A 1,500 mL/hr published output works out to 9.5 gallons a day, which is console territory, and because it evaporates water through wicks rather than atomising it there is no white dust and no mineral film on the furniture. The 3,000 sq ft claim is one of the more defensible in the catalog: the physics supports around 2,300, so it overstates by about a third rather than the three- and four-fold gaps common among the ultrasonics. The cost is a wick habit - four of them, around $40 a set - and a unit you fill through a hose and funnel rather than lifting a tank. Owners who moved from an ultrasonic mostly describe the absence of dust as the thing they noticed first.

Canopy sells cleanability, and on that promise it delivers better than anything else here: tank, tray, cap and grille all go in the dishwasher, the filter is on a 45-day clock the machine reminds you about, and because it evaporates rather than atomises there is no mist to land on anything. What $159 does not buy is capacity or control. There is no humidistat, and 2.5 litres across the advertised 36 hours is under half a gallon a day - a figure that supports something closer to 110 square feet than the 500 on the listing. As a nightstand appliance for one person's immediate airspace it is excellent. As the 500 sq ft room humidifier the marketing describes, it is not close.

Mechanically the Bedside 2.0 - same tank, filter, red light, nightlight and three soundscapes - sold with Canopy's baby-safe Little Dreams aroma kit and in nursery colours. The argument for it in a child's room is specific and good: no visible mist means nothing lands in a cot, no ultrasonic means no white dust in a room where a baby is breathing, and the dishwasher-safe parts mean the cleaning actually gets done at the interval it needs. The same capacity ceiling applies - this is one cot's worth of air, not a 500 sq ft nursery - and there is no humidistat to stop it when the room is where you want it.

An air washer works by turning textured evaporator mats through a water bath: air passes over the wet surfaces, picks up moisture, and drops some dust on the way. The appeal is that the mats are washed rather than bought by the season - Boneco says they go in the dishwasher or the washing machine - though it does sell replacement mats. Boneco's technical data gives 350 grams an hour, which is 2.22 gallons a day and supports about 547 sq ft, so the 540 on the listing is one of the few coverage claims in this catalog that its own maker's output figure actually backs. The rest of the arithmetic is as plain: a 4.5-litre bath, one silver stick a year, no filters, and about thirteen hours between fills if you are running it at the room it claims.