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A portable humidifier can help with allergies, dry skin and more. Here’s what to look for.


As the weather begins to turn cooler in the next few weeks in much of the United States, many people will be trading air conditioning for heat. Heating your home wards off the chill, but it also creates drier air, which can exacerbate allergies, make your skin feel like sandpaper and even crack wood furniture.

Some homes are equipped with a whole-house humidification system, but if you don’t have one and aren’t ready to make that kind of investment (between $150 and $500, plus installation, on average) there is a less costly option: a portable humidifier. These appliances — which come with a variety of features, depending on the model — put water vapor into the air to increase moisture.

As with any appliance purchase, consumers should do their homework and ask a lot of questions. “Look at your needs. Where are you using one, and for what purpose?” says Tobie Stanger, a senior editor at Consumer Reports, which recently updated its annual humidifier buying guide. Although the organization evaluated models that cost up to $800, you can find a good one with an excellent performance for less (sometimes a lot less) than $100.

“There is no perfect humidifier. None are plug-and-play. There’s always a trade-off,” says Rachel Rothman, chief technologist and director of engineering at the Good Housekeeping Institute.

Before starting your search, familiarize yourself with the basic types of humidifiers:

Evaporative: These use a fan to draw air through a wet wick or filter and release cool moisture into the air. Because of the fan, some can be noisy. Evaporative models often foster the growth of mold in the tank and well, so regular cleaning is a must.

Ultrasonic: These use a high-speed vibrating plate that turns water into a fine mist. They are simple to clean and are usually the quietest models. The downside is they also tend to disperse fine dust — particularly when used in a home with hard water — which can settle on surfaces and aggravate respiratory issues.

Warm-mist: These use a heating element to boil water and create steam. The boiling process helps reduce bacteria in the water before the mist is released. Because there’s no fan, warm-mist humidifiers are fairly quiet. However, the heating element and hot water pose a risk to children and pets, especially if the device tips over.

Here are some tips to help you decide which is right for your home:

Evaluate your options. According to Rothman, when people at the Good Housekeeping Institute look at humidifiers, they ask several questions: Is it easy to set up, easy to fill and truly portable? Is it easy to clean and maintain? Are the controls intuitive? Is it noisy? And how long is its run time? “Not only is tank capacity important, but so is tank design. Larger openings are easier to fill,” she says. If you can shop in stores and touch the models, do so. See how big the unit is, how it operates and how you put water in. Look at the water tank, and imagine how heavy or unwieldy it may be when filled. Some humidifier tanks fill from the bottom, meaning you must flip them upside down to fill them, then flip them up to place them back on the reservoir.

Find the optimal moisture level. “Many consumers think bigger is better, but you should get the appropriate humidifier to match your square footage,” Stanger says. Otherwise, you could wind up with too much moisture in the air, creating a breeding ground for bacteria. “In some cases, you may need separate units for each room,” she says. According to the Environmental Protection Agency’s Energy Star program, the optimal humidity level in a home is between 30 percent and 50 percent. In colder climates, when you are running your furnace, the humidity should be between 30 percent and 40 percent to prevent window condensation. Some humidifiers include a built-in hygrometer, an instrument that measures humidity in the air, so you can easily check room humidity. If not, you can buy one online for less than $10, Stanger says.

Decide where to put it. A flat surface, on the floor or elevated, and a few feet away from any object you don’t want to get wet is the ideal spot for a humidifier. Be careful if you have an ultrasonic model; water can start pooling on the surface below it, Rothman says. With a floor or tabletop model, you may need to place a towel or water-resistant cloth underneath it. Also, ensure that electrical cords or extension cords don’t pose a tripping hazard.

Calculate extra costs. Look at the extras and calculate how much it will cost to run your unit.

The wick (about $5 to $20) in an evaporative humidifier, which removes most mineral deposits, should be replaced every month or so (when the wick turns brown, you smell an odor or output drops). To extend wick life: Each time you clean your unit, rinse the wick and flip the bottom side to the top, because the top tends to dry out quicker than the bottom, which sits in the water well.

For homes with hard water, an ultrasonic humidifier may produce a fine, white dust. Using distilled water instead of tap can reduce the dust, but assuming you refill your tank daily, that can mean buying seven gallons or more of distilled water per week. Demineralization cartridges designed to trap minerals before they become airborne are another potential remedy. These run between about $9 and $13 and should be replaced every one to three months, depending on water hardness.

Plan to keep it clean. There’s no way around it: Portable humidifiers are a magnet for bacterial growth. Some models are easier to clean than others, and you may want to factor that into your buying decision. Always read the instructions, but expect to empty the tank daily, even if you only use it at night in your bedroom.

A general rule of thumb is to clean your unit at least once a week. Good Housekeeping recommends using one to two cups of undiluted white vinegar and swishing it around in the tank before placing the tank back onto the base, so it drains into the reservoir. Leave the vinegar in for 15 to 20 minutes, then empty the tank and base, and use a toothbrush or cotton swab to remove mineral deposits. Wipe down the cap with a cloth, rinse everything thoroughly with water and let it air dry. For a deeper clean, instead of vinegar, use a solution of one teaspoon of bleach to one gallon of water. “Proper cleaning is a pain, but you must be willing to invest the time and effort,” Rothman says. “If you aren’t willing, then don’t use a portable humidifier.”

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