Does a humidifier help you breathe better at night?

A humidifier can make dry air more comfortable to breathe, especially in winter when heating dries out the bedroom. It won't open a blocked nose on its own, and there's very little research on whether it improves sleep. If you use one, keeping the humidity in range and the tank clean matters more than which model you buy.

What does a humidifier actually do for breathing?

The EPA describes the purpose of home humidifiers plainly. People use them to relieve the discomfort of a dry nose, throat, lips and skin. Cleveland Clinic adds that dry air can irritate the nose and lungs, and that a humidifier helps thin mucus, which makes coughing or blowing your nose more effective.

Dry air may also make nights harder. Cleveland Clinic says that in dry conditions you're at greater risk of waking up coughing or having sleep interrupted by nosebleeds and a dry mouth.

Cleveland Clinic also links dry airways to snoring, saying you're more likely to snore when your airways are dried out. If your snoring is worse in winter when the heating is on, dry air may be playing a part. It's only one possible factor, and our guide on how to stop snoring covers the others.

That's a reasonable case for comfort. It's not the same as evidence that a humidifier improves sleep, and that kind of evidence is mostly missing.

What does the research say?

Direct studies of bedroom humidifiers and sleep are scarce. The closest well-reviewed research looks at colds. A 2017 Cochrane review pooled six trials with 387 people who breathed heated, humidified air through a device. The authors found the evidence didn't show any benefit or harm for cold symptoms, and they rated its quality as low.

That review tested a specific treatment device rather than a room humidifier, so it doesn't settle the question either way. The fair summary is that a humidifier is a comfort measure. If dry air bothers you, it may help you feel better. If your nose is blocked by swelling, allergies or a structural problem, added moisture won't fix the cause.

Does a humidifier help with dry mouth at night?

A humidifier may make a dry mouth less uncomfortable, but it won't stop the main cause. The American Dental Association notes that saliva flow drops to its lowest levels during sleep, and that mouth breathing makes dry mouth worse at night. If you wake with a parched mouth every morning, look at why you're breathing through your mouth. Why do I wake up with a dry mouth? goes through the usual reasons, and nasal vs. mouth breathing covers why the route matters.

The ADA also lists other things that dry the mouth, including many common medicines such as antihistamines, decongestants and some blood pressure drugs, along with alcohol, tobacco and a lot of caffeine. A humidifier won't change any of those.

Can mouth tape and a humidifier work together?

Mouth tape and a humidifier can work together because they tackle different parts of the same problem. A humidifier adds moisture to the air in the room. Mouth tape keeps your lips closed so you breathe through your nose, which helps stop your mouth drying out from hours of mouth breathing. If your nose is clear and your mouth tends to fall open at night, using both is a reasonable setup for waking up less parched.

Start with our two-minute nose test. If you pass, how to start mouth taping covers the first few nights, and lip balm and mouth tape explains how to keep dry lips comfortable without stopping the tape from sticking.

If you want to try mouth tape and nasal strips together, our pick is the Titan Sleep System, which pairs TitanAir Nasal Strips with Titan Mouth Tape.

How humid should your bedroom be?

Cleveland Clinic cites the EPA's recommendation to keep home humidity between 30% and 50%. The EPA's own guidance is to avoid going above 50%.

Going too high causes its own problems. The EPA warns that excess moisture encourages dust mites and mold, both common allergy triggers. The AAAAI notes that dust mites thrive in warm, humid places like bedding and recommends keeping humidity low for people with mite allergy. So if you're allergic to dust mites, a humidifier set too high could leave you stuffier rather than less. The EPA notes that hygrometers, sold at hardware stores, can measure humidity levels. If allergies are part of your nighttime congestion, see why allergies feel worse at night.

Which type of humidifier should you choose?

Cleveland Clinic describes the main types. Central humidifiers are built into a home's heating and air conditioning and cover the whole house. Evaporators blow air through a moistened filter. Impeller and ultrasonic models make a cool mist, one with spinning disks and the other with vibrations. Steam vaporizers heat water to make vapor, and the EPA notes that "warm mist" models are a type of steam vaporizer that cools the steam before releasing it.

The type matters for cleanliness. The EPA says impeller and ultrasonic models generally disperse the most microorganisms and minerals into the air. Evaporative and steam models can still grow microorganisms in a standing-water tank but generally release less, if any, of these into the air, and aren't expected to release many minerals. Steam models bring their own risk of burns, which matters in a child's room. Whatever you choose, the cleaning routine below matters more than the label.

How do you clean a humidifier safely?

Cleaning is where the EPA puts most of its attention. Its guidance says ultrasonic and impeller (cool mist) humidifiers can spread microorganisms and minerals from the tank into the air. Cleveland Clinic warns that a dirty humidifier can grow mold and bacteria.

The EPA recommends:

1. Use distilled water. Distillation is the most effective way to remove minerals, which otherwise get sprayed into the room.
2. Empty the tank, wipe all surfaces dry and refill it with fresh water every day.
3. Clean portable humidifiers every third day. Empty the tank and scrub it. Follow the manufacturer's advice on cleaning products, and if there isn't any, clean every surface that touches water with a 3% hydrogen peroxide solution.
4. After using any cleaning agent, rinse the tank thoroughly with several changes of water so the chemicals don't end up in the air.
5. If white dust appears on surfaces, consider a demineralization cartridge or filter if your humidifier is designed for one, though the EPA notes their effectiveness varies widely.
6. Keep steam vaporizers out of reach of children, since steam and boiling water can cause burns.

Cleveland Clinic gives similar advice: change the water daily and wash and sanitize buckets or filters every two to three days. It also cautions against adding essential oils to a humidifier that isn't designed for them, as they can damage it. The same goes for vinegar, which it says is for cleaning the unit rather than adding to the water, and for decongestant rubs, which can damage the humidifier and may contain ingredients that aren't safe for everyone.

At the end of the season, the EPA says to clean the unit, make sure every part is dry and store it somewhere dry, then clean it again before you next use it. Cleveland Clinic suggests replacing a humidifier once it has stuck-on mineral deposits you can't clean off.

When should you stop using it?

The EPA says to stop using your humidifier and contact your doctor if you have breathing symptoms that seem to come with using it, even if you're following the cleaning directions. It notes that the young, older adults and people with lung disease or respiratory allergies may be more sensitive to airborne pollutants. Cleveland Clinic gives the same advice: if you think your humidifier is affecting your breathing, stop using it and talk to a provider.

Is a humidifier worth trying?

If your bedroom air is dry and you wake with a dry nose or throat, a humidifier is a low-risk thing to try, provided you keep it clean and the humidity under 50%. The EPA says to use one only when conditions call for it, and Cleveland Clinic suggests checking your humidifier's instructions for how long to run it, which can be anywhere from about two hours to 10 or 12 hours depending on the unit. Give it a week or two and judge it on whether you feel more comfortable, not on promises of better sleep.

If your nose is blocked most nights, or you snore loudly with gasping or pauses in breathing, that needs a doctor rather than a gadget.

Read next

• How to sleep with a stuffy nose
• What's the best bedroom temperature for sleep?

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.