Should You Run a Humidifier in Winter?

Humidifier harms

If you don’t clean your humidifier properly, it can quickly become a breeding ground for germs and then spew them into the air.

In her 2022 study in Indoor Air: International Journal of Indoor Environment and Health, Andrea Dietrich, a civil and environmental engineering professor at Virginia Tech, wrote that people should be more aware of potential harms of humidifiers. Lung injury is possible, though the incidence of hospitalization is low, she wrote.

Specifically, the devices can increase risk of humidifier lung, a type of allergic reaction that causes lung inflammation (hypersensitivity pneumonitis) that’s brought on by contaminated humidifiers.

Pretty much anything in the water you put into a humidifier — chemicals, metals, particles, fibers and microorganisms — can be released into your indoor air as those droplets evaporate, according to the report on ultrasonic humidifiers. That’s why it’s imperative to use the type of water recommended by the manufacturer (typically, distilled water is the norm).

Using a humidifier also can increase the risk of dust mites, according to the American Academy of Allergy, Asthma & Immunology.

Mold can also grow in your humidifier, whether you’re using a cold- or warm-mist unit, Galiatsatos notes. We all breathe in some mold, though most mold doesn’t cause infections. Instead, the machines can cause mold to grow, which may lead to an allergic reaction to the mold, with symptoms like coughing or breathlessness, he explains.

If you have an immunodeficiency, such as human immunodeficiency virus (HIV), or malnutrition, you may be more prone to mold that causes an infection. If you suspect there’s an issue, talk to your doctor, who can test for potential ties to mold, he adds.

7 tips for using a humidifier correctly

If you use a humidifier, these tips can help you keep the unit in good shape so you can reap potential health benefits.

1. Use a cool-mist humidifier

Galiatsatos recommends using a cold-mist humidifier, as a warm-mist machine could come with burn risks.

2. Use it at the right time

You can use a humidifier any time of year that it may help, but use it only when needed, Galiatsatos advises. Some people who often get nosebleeds may be good candidates for more frequent use, he adds. As for how long per day to run the unit, Galiatsatos says he probably wouldn’t use it more than once a day and not all day.

3. Pick the right water

The type of water you use matters, Galiatsatos says. More expensive machines may use filters, so you may not have to use distilled or demineralized water, though many portable units require it. When the instructions specify which type of water to use, follow the directions. If you wouldn’t drink the water you put into the machine, you probably shouldn’t use it, he adds. Some machines say they can use tap water.

Don’t use water treated with a water softener or a carbon/ion exchange filter to purify tap water, as they can replace minerals like calcium and magnesium with sodium and potassium, which will produce potentially harmful particles that can make respiratory issues worse and introduce metals into your body, Dietrich said in an article last year on the university’s website.

4. Clean the unit correctly

Dietrich said to avoid cleaning your unit with chemical disinfectants; they can be harmful if they become airborne. The EPA recommends cleaning portable units every third day; Galiatsatos says to follow the manufacturer’s instructions. Depending on the machine, typical cleaning methods include regularly removing water from the unit, scrubbing inner parts with a brush or running vinegar through it. Solutions of bleach or hydrogen peroxide are also commonly used in some units.

When buying a machine, check how often it’s supposed to be cleaned and what type of maintenance is needed. If it seems like too much, don’t purchase that unit, Galiatsatos advises.

“Once you use it, you have to disinfect it,” he says. If you don’t clean it properly, it becomes a “harbinger of microbes.” Don’t assume the machine will disinfect itself.

5. Crack a window

This may not be ideal if it’s too cold, but getting some fresh air into the room for a bit where you use the humidifier may disperse concentrated particles that may be harmful, Dietrich advises.

6. Check the humidity level in the air

Ideally, you want between 30 and 50 percent humidity, Galiatsatos says. Don’t go above 50 percent humidity, the EPA warns. A hygrometer can help you measure the humidity levels your space, and they’re typically under $10.

7. Keep the area around your machine dry

Make sure the mist isn’t directly hitting furniture or making nearby bedding damp, the Mayo Clinic recommends.

Other Ways to Get Relief

Stop using a humidifier if you feel like it’s doing more harm than good, Galiatsatos says.

If you’d like some relief from congestion or dry nasal passages, he suggests:

• Saline, which is his favorite method of decongesting and moisturizing nasal passages. You can opt for a neti pot or saline sprays. These may not be right for frequent nosebleeds; if you have those, talk to your doctor about your best options.
• Steam showers can provide some temporary relief.
• Decongestants may ease congestion
• For dry skin, Lockey recommends a shower followed by a moisturizer.