Top Reasons to Buy a Cool-Mist Humidifier

They’re safer around kids and pets. And they provide other benefits.

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Illustration of a humidifier with cool blue clouds coming out of it. Illustration: Getty Images

Cool-mist humidifiers make up the bulk of the humidifier market in the U.S. And for good reason. 

Unlike warm-mist humidifiers—aka vaporizers—cool-mist versions add moisture to indoor air without boiling water and producing steam. With no potential to burn or scald, cool-mist humidifiers are the only humidifier type that pediatricians recommend for households with babies and young children. 

“They’re also the best choice for homes with pets prone to investigating mysterious appliances,” says Misha Kollontai, who leads humidifier testing at Consumer Reports. Translation: They’ll save your sniffing Snoopy’s snout.

Read more on the advantages of cool-mist humidifiers below, and see the best cool-mist models among each of the humidifier sizes Consumer Reports tests. ​​For test results and more options, CR members can check our complete humidifier ratings, which include units that range from personal size all the way up to consoles that can humidify 1,000 square feet or more.

More Reasons to Go Cool

Even in homes without curious critters or toddling tots, cool-mist humidifiers have benefits. Here’s how they excel over other types:

More on Humidifiers

Energy efficiency. Cool-mist models use significantly less energy than warm-mist models. The reason is that they work without boiling water, which requires a fair amount of electricity, Kollontai says. Depending on the unit’s style, a cool-mist humidifier uses one of two mechanisms to bring moisture into the air.

Evaporative cool-mist humidifiers use a fan to blow air through a wet wick; the air cools as it picks up moisture from the wick. Periodically, you’ll need to replace a filter or wick, which can run from $10 to $20.

Ultrasonic cool-mist models—the majority of units in CR’s ratings—use small vibrating diaphragms called nebulizers to create a mist. Ultrasonic units typically are less noisy than evaporative models because they have no fan. However, their mist can leave a white dust—tiny particles of mineral precipitate—on surfaces. (To prevent that dust, you can use distilled or filtered water instead of tap water.)

Help for stuffy noses. Cool mist can help shrink swelling in nasal passages, making breathing easier, the Food and Drug Administration says. By contrast, warm mist can cause nasal passages to swell, making breathing more difficult—another reason the FDA doesn’t recommend their use for infants with coughs and colds.

Convenience in small sizes. In our ratings of small humidifiers, cool-mist models were judged more convenient as a whole vs. small warm-mist units—better known as vaporizers—reflecting factors such as ease of operation. Several small cool-mist units in our ratings have humidistats, which turn off the unit when the air reaches a set humidity level; none of the small vaporizers in our ratings has that feature. Small vaporizers typically don’t even have a power switch; they start working when you plug them into an outlet. (They, do, however, shut off automatically when the tank is empty.)

More shopping choices. Cool-mist models make up more of the portable humidifier market than other types, says Marion Wilson-Spencer, a market analyst who covers humidifiers for Consumer Reports. In CR’s ratings, you can find cool-mist humidifiers in every size we test, including travel models, units for small, medium, and large rooms, and consoles for very large rooms of 1,000 square feet or more. In our ratings, you won’t find warm-mist units in travel or console sizes; you also won’t find dual-mist units in small, medium, or travel sizes.

Where a Cool-Mist Model Has No Advantage

One area where cool-mist humidifiers have no edge is in how well they do their basic job: adding moisture to the air. “Cool- and warm-mist units are equally effective at humidifying,” Kollontai says. 

There’s also no way to generalize on which type is easier to clean. “It depends largely on the design,” Kollontai says. With either type, though, it’s crucial to clean the components regularly to prevent the growth of mold spores and other nasties that can lead to illness. Check the manufacturer’s directions for cleaning, as well as Consumer Reports’ advice on this key task.

When to Opt for a Warm-Mist or Dual-Mist Humidifier

The main reason for using a warm-mist humidifier is noise. Warm-mist models tend to be quieter because they don’t need a fan, nebulizer, or vibrating diaphragm to move moisture into the air. “The steam naturally escapes the tank,” Kollontai says. 

For the best of both worlds, consider buying a dual-mist version, which lets you choose between cool and warm mist. There are five dual-mist units in CR’s ratings; all have Overall Scores of Good or Very Good. “A dual-mist model allows you to take advantage of the soothing warm mist only when you truly think you need it, and to take advantage of the energy savings of cool otherwise,” Kollontai says. 

Just steer clear of dual-mist units if you have kids or pets, because an inadvertent turn of the dial or press of a button can activate potentially scalding steam.

Best Cool-Mist Humidifiers From Consumer Reports' Tests

Choose the size that’s closest to the square footage of the space you want to humidify.

Travel/Personal (up to 25 sq. ft.)

Small Room (26 to 299 sq. ft.)

Medium Room (300 to 499 sq. ft.)

Large Room (500 to 999 sq. ft.)

Console (1,000+ sq. ft.)

Tobie Stanger

I cover the money side of home-related purchases and improvements: avoiding scams, making sense of warranties and insurance, finding the best financing, and getting the most value for your dollar. For CR, I've also written about digital payments, credit and debit, taxes, supermarkets, financial planners, airlines, retirement and estate planning, shopping for electronics and hearing aids—even how to throw a knockout wedding on a shoestring. I am never bored. Find me on Twitter: @TobieStanger