Picking the right humidifier
Humidifiers can help restore the balance of moisture in your home, particularly in dry climates and during the winter. They also can alleviate discomfort and symptoms associated with colds, asthma and other ailments by keeping the air moist.
The two main types of humidifiers are cool-mist humidifiers and warm-mist humidifiers.
There are three types of cool-mist humidifiers. Most popular are ultrasonic humidifiers, which use high-frequency sound waves to vaporize water. They are also the quietest. Some ultrasonic humidifiers also can emit warm mist. Evaporative humidifiers soak up water into a wick and use a fan to expel the moisture. As a result, these models can be noisy. Humidifiers can be inexpensive, but replacing their wicks or filters is an ongoing cost. Some cool-mist humidifiers use impellers to force (impel) water into the air as a fine mist; however, we found no positive reviews for those humidifiers.
Warm-mist humidifiers (sometimes called vaporizers) boil the water before expelling it as steam. This can eliminate bacteria that's present in the water if it's heated to a true boiling point of 212 degrees Fahrenheit, but it also means that minerals can build up in the tank and on the heating element over time, and they're not always easy to clean. Some people prefer warm-mist humidifiers, saying the heated vapor is easier to breathe (especially if you're congested) and that it gently raises room temperature. But experts say the difference between cool mist and warm mist is minimal, and doctors, such as those at the Mayo Clinic caution that warm-mist humidifiers pose a safety hazard because they can be tipped over by young children, scalding them. They are also less energy efficient. Expert reviews are generally neutral to negative for this type of humidifier, and users aren't that much more pleased. In general, if you want a humidifier that can emit warm mist, we recommend an ultrasonic model that can produce both cool and warm moisture.
Finding the best humidifiers
In selecting the best humidifiers we weighed several factors, including performance (moisture output), ease of use, noise and the ownership experience, looking for both the best performers, and those that deliver the best bang for the book.
Both experts and users were consulted. On the expert side, it's tough to find a better resource than ConsumerReports.org, which tests more humidifiers than anyone else. However, not all of the humidifiers listed on the site are current models (though many are) and the results of its hands-on tests can only be viewed by subscribers. TheSweetHome.com also consults ConsumerReports.org and other experts and reviewers, but then conducts its own testing to find the best choice. We also looked at comparative reviews conducted by Good Housekeeping and Slate; though both are now a little dated, enough of the models covered there are still available to make both resources somewhat useful.
While experts often agree on which humidifiers are best, we found a sometimes startling divergence of opinion when it came to user reviews. This is likely because issues that don't always manifest during the short time experts have to evaluate a humidifier do show up after weeks or months of use. In some cases, issues apply to one user -- hard water, for example -- but don't apply to others. As a result, user ratings for humidifiers as a class are often mixed. Be that as it may, we consulted the user reviews at Amazon.com, HomeDepot.com, Lowes.com, Sears.com and others in compiling these recommendations.
Ultrasonic humidifiers earn top marks from reviewers
When it comes to choosing the best humidifier overall, expert reviewers typically place ultrasonic models at the top of their lists. These best of these machines are capable of producing warm or cool mist. They are also quieter than other types of humidifiers and lack a messy-to-clean filter. Their downside is a higher propensity to emit dust -- an especially annoying problem for those with hard water. Remedies include using distilled water or a demineralization cartridge, if one is offered.
Among the top choices, expert reviewers point to the Air-O-Swiss AOS 7135 (Est. $180) ultrasonic humidifier. This humidifier can produce warm or cool mist and is suitable for rooms up to about 650 square feet. The water tank on the Air-O-Swiss AOS 7135 is detachable and transparent, which makes it easy to clean and allows you to keep an eye on the water level. A digital humidistat allows you to adjust the humidity in the room to your desired level. This humidifier comes with an Air-O-Swiss AOS 7531 demineralization cartridge (Est. $16), which needs to be replaced every two to three months (or more often with hard water) to prevent the release of minerals into the air -- a frequent complaint with humidifiers. There's also an Air-O-Swiss AOS A200 Hydro Cell (Est. $30), which should be replaced every two months or so to prevent bacteria from taking root in the water tank between cleanings.
The Air-O-Swiss AOS 7135 does extremely well in professional reviews. It's a recommended pick by one independent expert, and is named the best humidifier overall by TheSweetHome.com. Seamus Bellamy writes that the AOS 7135 is quiet, efficient in raising humidity levels, and can be set to maintain a safe humidity level, and then left alone until it's time to refill or clean the humidifier. The expert review at AllergyBuyersClub.com notes that more of the site's staff members own the AOS 7135 than any other humidifier it sells. "All in all, the Air O Swiss 7135 is a sensible and reliable solution for anyone looking to improve the air quality in their home or office," they say.
User reviews, however, are a bit of a mixed bag. Amazon.com hosts the most of these, and owners are of a decidedly split mind. The majority is mostly to completely pleased, however this humidifier's overall score is dragged down by owners that complain about leaking, inconsistent humidity, or mineral dust; the latter is especially a problem for those with very hard water or who skip using the demineralization cartridge. At AllergyBuyersClub.com, feedback is a bit better -- a 4.2 star rating with 78 percent of buyers saying that they would recommend the AOS 7135 to a friend.
AllergyBuyersClub.com names the Air-O-Swiss Ultrasonic 7144 (Est. $ 200) its best humidifier. It is also named as a "splurge-worthy pick" in the comparison tests conducted by the Good Housekeeping Research Institute, and it earns a score of 8 out of a possible 10 from Wired. But user reviews for this humidifier are once again mixed (as they are for virtually all humidifier models, regardless of price). Compared to the AOS 7135, the AOS 7144 is a bit sleeker, with a more sophisticated silver/black finish (the 7135 is blue and white). Both offer the same 3.5-gallon-per day output, but the AOS 7144 has a smaller tank (1.5 gallons versus 2 gallons), which means you'll be refilling it a little more often. Availability for the AOS 7144 has become limited, but the model remains current and can be purchased from Air-O-Swiss.
For smaller rooms (up to 500 square feet), the SPT SU-4010 Ultrasonic Dual-Mist Warm/Cool Humidifier with Ion Exchange Filter (Est. $80) earns excellent ratings across the board in one independent test and is named a Best Buy. This SPT (formerly Sunpentown) humidifier is also the budget pick at TheSweetHome.com and is highly rated by AllergyBuyersClub.com. Like the Air-O-Swiss 7135 humidifier, it is designed to produce cool and warm mist, with variable humidity levels. However, this model does not include a humidistat. It does have a demineralization cartridge (called the Ion Exchange Filter), which should be replaced every six months. Other features include overheat protection and a split rotating nozzle to direct mist in two directions simultaneously. This model is energy efficient (using up to 43 watts on the cool-mist setting and 90 watts for warm mist) and very quiet.
However, we once again noticed reliability complaints. At Amazon.com, more owners are happy than not, but we saw reports of humidifiers breaking down anywhere from a week to four months after purchase, and we also read several reports of leakage, often severe. However, some owners identify the source of the leak being improperly seating a sealing ring after filling and that carefully following the maker's refilling instructions should eliminate the problem.
Elsewhere in this Issue:
Best Cool-Mist Humidifiers | Best Whole House Humidifiers | Best Warm Mist Humidifiers | Buying Guide | Our Sources