Cool-Mist Humidifiers

Cool-mist humidifiers are safe but have high filter costs

If you use a humidifier all year, a cool-mist model is the way to go; because these don't raise the room temperature or emit steam, they are a good choice for warm, dry climates. Cool-mist humidifiers use a fan, however, so they can be noisy. Though the units themselves can be inexpensive, the ongoing filter costs are a common complaint. Because these models don't boil water, there's no burn risk and less energy cost.

A cool-mist humidifier, the Kenmore 15408 (*Est. $110), is rated highest by Slate.com's Laura Moser. This Kenmore humidifier is fairly compact for a machine with a 1,700-square-foot coverage area and an 8-gallon daily output. The water tank can be filled twice at a time, cutting in half the frequency with which it runs dry, though it will still need to be refilled throughout the day: the "double tank" holds 2.4 gallons. The unit is designed to quickly bring the surrounding area up to a preset humidity level, after which it automatically cycles off. Replacement filters cost $18 and should be replaced every two to three months.

Sears also offers a larger-capacity evaporative humidifier, the 12-gallon Kenmore 15412 (*Est. $140), with coverage of 2,500 square feet. ConsumerGuide.com's review cites the 12-gallon Kenmore humidifier for its four speeds and an LED screen that displays both the target humidity and the actual humidity. While this model outputs up to 12 gallons per day, the tank itself holds 3.9 gallons of water.

Another nice feature of the larger Kenmore humidifier is a side-fill bottle that fits under most faucets. Like its 8-gallon counterpart, the Kenmore 15412 also has a double-fill tank system. The first fill drains directly into the machine, after which you immediately refill it. Moser calls the system "brilliant," adding that it "cuts in half the number of times you have to stop life to schlep back and forth" with water. Owners posting on Sears.com are moderately satisfied with their evaporative humidifiers, with the caveat that many have had difficulty finding replacement filters. One user reports that compatible filters are readily available online from other retailers, however.

Good Housekeeping's engineers choose the Honeywell HCM-300T (*Est. $80) as the top performer in its test. This compact cool-mist humidifier uses ultraviolet light to sanitize the water, helping to reduce germs, bacteria and mold. It outputs up to 3 gallons of water per day -- enough to humidify about 1,000 square feet -- and holds 1.6 gallons in the tank. Good Housekeeping reminds owners that this unit, as well as all other humidifiers, must still be cleaned regularly. It praises the Honeywell HCM-300T for raising room humidity quickly and for its low electricity cost. Laura Moser of Slate.com likes the space-saving tower design and the ultraviolet (UV) antibacterial feature of the Honeywell HCM-300T, which was "in hot contention for the top spot" for the first few weeks of her test. However, during the third week of testing, the water tank leaked all over her floor. Several owners of this model also report eventual leakage problems on online review sites.

Another compact Honeywell humidifier, the Honeywell HCM-631 (*Est. $50), is Good Housekeeping's second-place winner overall. While it lacks a UV light, it includes filters for capturing dirt, dust and pollen, as well as for reducing mineral buildup, mold and bacteria. Replacement filters (*Est. $13) can last up to three months, depending on water quality and usage. The HCM-631 comes in black; there is also a white version, the Honeywell HCM-630 (*Est. $50). This humidifier raises humidity levels quickly in Good Housekeeping's tests. It outputs 3 gallons a day -- enough for about 1,000 square feet -- and holds 1.5 gallons in the tank.

Owner reviews are mainly good for these small Honeywell humidifiers at Amazon.com, but few owners are completely happy with them. Most say that while they're not silent, the noise doesn't keep them up at night. The main complaint is the ongoing cost of the filters, and some owners say the filters only last about six weeks. So while the Honeywell HCM-631 is inexpensive to buy, filter costs may make it a better choice for seasonal use than for year-round operation.

Ultrasonic humidifiers are quiet, versatile

Ultrasonic humidifiers use high-frequency vibrations to drive water into the air. This makes them the quietest of all humidifier types. Most of these produce cool mist, but now there are ultrasonic humidifiers that offer the option of either cool or warm humidification from the same machine. The downside: They are more expensive than others.

With Air-O-Swiss Ultrasonic humidifiers, you can select a pre-heating function to generate warm mist. AllergyBuyersClub.com rates the Air-O-Swiss 7135 (*Est. $150) and Air-O-Swiss 7133 (*Est. $140) humidifiers as excellent. Owners seem to like them, too, with the 7135 receiving the better ratings. On the Air-O-Swiss 7135 humidifier, a built-in hygrometer that measures humidity in the surrounding air and a digital LCD display add to the price; however, these features allow you to control the humidity level more easily. If you need to run a humidifier daily for several months, an Air-O-Swiss humidifier might be worth the extra cost. Good Housekeeping's "splurge-worthy pick" is the Air-O-Swiss 7144 (*Est. $200), which has a more attractive design.

Suitable for rooms up to about 600 square feet, Air-O-Swiss humidifiers feature an ionic silver stick designed to prevent microbial growth. This stick (*Est. $30) should be replaced annually. The water tanks on Air-O-Swiss humidifiers are detachable and transparent.

Air-O-Swiss humidifiers also have a demineralization cartridge (*Est. $16) intended to eliminate the white dust problem experienced with some humidifiers. This cartridge needs to be replaced every two to three months. AllergyBuyersClub.com says that the Air-O-Swiss humidifiers will disperse dust if they are filled with softened water. Owners posting at Amazon.com complain that dust is still a problem with the Air-O-Swiss 7133, but reviews there report fewer dust problems with the 7135 humidifier. We haven't read enough feedback on the Air-O-Swiss 7144 yet.

For smaller rooms (up to 400 square feet), the Germ Guardian Manual Ultrasonic Humidifier is highly rated by AllergyBuyersClub.com and does well in Laura Moser's Slate.com evaluation. Its attractive, compact design and silent operation make it a good choice for a bedroom, and it is easy to maintain with no filters or cartridges to buy. The design incorporates nano-silver technology to disinfect the unit and prevent mold and bacteria.

This humidifier is available in two versions. The Germ Guardian H2000 (*Est. $130) lacks the adjustable humidistat found in the more expensive Germ Guardian H3000 (*Est. $170). Germ Guardian humidifiers are priced higher than other brands, but owners say they are durable and require no additional expense for filters. The manufacturer recommends using distilled water if dust is emitted, which potentially adds to the cost.

Also for small areas, the Crane Adorable Ultrasonic Humidifier (*Est. $35) may be worth considering. As the name indicates, this humidifier is marketed for its charm and appeal to children, taking the shape of various animals and cartoon characters. Despite the somewhat silly looks, the Crane humidifier gets good reviews from more than 1,000 users at Amazon.com, Target.com and other retailer websites. With its 1-gallon tank, the Crane will run for up to 11 hours (longer, according to some owners) and is intended for rooms of approximately 250 square feet. It automatically shuts off once the tank is empty. However, as an ultrasonic humidifier, the Crane discharges the minerals found in most tap water as white dust. A demineralization cartridge is available to cut down on white dust, but it isn't always effective. Although it's inexpensive, we read quite a few complaints about early breakdowns, and some owners say it is difficult to clean properly.

Whole-house humidifiers

If you need to humidify several rooms or a whole apartment, you may want to consider a console humidifier. Console humidifiers are large evaporative humidifiers. None of the most recent humidifier reviews we found include a console model, however.

Kenmore makes a console-style humidifier, the Kenmore 14416 (*Est. $160), which has a 12-gallon output and coverage of 2,500 square feet. The tank holds 4.75 gallons. It has an adjustable humidistat to control the desired output, and it refills at the top of the unit. Owner reviews of the Kenmore 14416 console humidifier are mixed. Most say it does a fine job, but some complain about its durability.

If you have forced hot-air heating and need a whole-house humidifier, an alternative to a console model is an in-duct unit. You don't have to find space for it in your house, and you also don't have to keep refilling it because it's attached to your home water supply. Of course, humidification will occur only when the forced-air system is running. Professional installation may be required because plumbing and electrical wiring have to be put in place.

One in-duct model is the Desert Spring Rotary Disc Furnace Mount Humidifier (*Est. $230). Its rotating-disk design requires little maintenance, and the unit doesn't incorporate the problematic humidifier pad that often clogs up other furnace units. Mineral particles are rinsed from the disks when they re-enter the reservoir and fall into a basin from which they can be drained periodically. We did not find reviews for this model, however.