Honeywell humidifiers

Eighteen gallons a day against a published 4,500 sq ft - almost exactly what the load calculation says 18 gal/day supports, which makes this the most precisely honest coverage claim of any whole-house unit here. Like the Aprilaire 700 it carries its own blower, so it humidifies on mild days when a bypass unit sits idle, and Honeywell specifically recommends it with variable-speed and multi-stage furnaces where the burner cycles less. It undercuts the Aprilaire 700 by $60 on hardware.

Honeywell's direct answer to the Aprilaire 600, matching it at seventeen gallons a day. Honeywell quotes its coverage twice on the same page: "up to 4000 sq. ft." in the features and "up to 18,000 cubic feet" in the spec table - and 18,000 cubic feet at an eight-foot ceiling is only 2,250 sq ft, so the two figures do not describe the same house. The square-foot figure is the one it markets, and against seventeen gallons a day, which supports about 4,200 sq ft, it is close to honest. The PerfectFLO tray meters water onto the pad instead of flooding it, which is where the water-saving claim comes from.

The long-running default in this category, and the arithmetic explains why. Honeywell's manual gives 2 gallons a day of output against the 500 sq ft it is sold for - a room that needs almost exactly that - making this one of the few portables in the catalog whose coverage number the physics supports outright. It was sold from 2011 largely unchanged until Honeywell discontinued it; the tank and tray go in the dishwasher, and it evaporates rather than atomises, so there is no white dust. The costs are a wick habit, a fan you can hear, and no humidistat at all: three speeds, and you are the humidistat.

Honeywell's answer to the two complaints levelled at the HCM-350: no digital humidistat, and a tank you have to carry upside down to the sink. The HEV620 is a tower with a top-fill opening, a digital humidistat that will actually hold a target, and a timer. Its 300 sq ft claim against 2 gallons a day of output is one of the most conservative ratios in the catalog - the output supports closer to 490 - which is worth knowing if you have been talked out of it by a spec-sheet comparison against an ultrasonic promising 750. Honeywell now sells it in black (HEV620B); the white HEV620W pictured is discontinued.

Honeywell's filter-free line exists because plenty of people would rather buy no consumables than buy the right ones. There is no wick and nothing to replace, which keeps ownership about as cheap as it gets here - and it is an ultrasonic with no demineralisation media, so on hard water the minerals that a wick would have caught end up on the furniture instead. A gallon tank and 24 hours works out to about a gallon a day, near enough to what its 300 sq ft claim needs, making this one of the more honest small ultrasonics on that particular number.

Take the HCM-350's mechanism and move the fill to the top: water goes in through a funnel on the lid, so nothing has to be carried to the sink, and that is most of what "Easy to Care" means. The trade is capacity: a 1-gallon tank against the 350's 1.1, no UV, and no humidistat here either. Neither Honeywell's manual nor its store page says any part is dishwasher safe, unlike the HCM-350, whose tank and tray are. At the 36 hours Honeywell claims it is moving two thirds of a gallon a day, which is a bedroom's worth; the 360 sq ft it is sold for would take closer to 1.5 gallons a day and drain the tank in about 16 hours.