How bad is it really to sleep with a fan on?

Sleeping with a fan on can lead to mild health issues, but there are ways to lessen its negative effects.

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For some people, sleeping with a fan on is a key part of their nighttime routine. The brisk breeze helps keep you cool and comfortable through the night, not to mention the gentle hum can produce enough white noise to block out a car horn or snoring bed partner. But is sleeping with a fan bad for you?

Well, that depends: sleeping with a fan is good in some ways, but can be harmful in others. We consulted with experts to understand when fans aren’t safe and what you can do to change that (including whether to say goodbye to your favorite fan).

6 ways sleeping with a fan on can compromise your health

Here’s why sleeping next to a fan may be less than ideal for your well-being:

1. It can trigger allergies or asthma

“In patients allergic to dust or other indoor antigens, a fan may stir up particles in the room or disperse accumulated dust on the fan itself,” says Raj C. Dedhia, MD, MSCR, associate professor of otolaryngology and sleep medicine at the Perelman School of Medicine at the University of Pennsylvania.

Yes, your fan can cause dust mites, pet dander, and more, which can exacerbate your allergy or asthma symptoms.

2. It can contribute to poor indoor air quality (depending on where you live)

The combination of opening a window and running a fan at night might seem like a smart strategy to keep you cool while you sleep, but it could do you more harm than good.

If you live in an urban environment where there are a lot of diesel emission particles, a fan can circulate these outdoor air pollutants indoors and direct them directly into your upper airways, says Sam Huh, MD, chief of otolaryngology at Mount Sinai Brooklyn Hospital.

“It’s very harmful whether you’re allergic to dust or not,” says Dr. Huh.

Indeed, these pollutants can deteriorate the quality of indoor air. And poor indoor air quality can cause or contribute to the development of infections, lung cancer and chronic lung diseases like asthma, according to the American Lung Association.

3. It can cause congestion

If you’ve ever had a stuffy nose after sleeping with a fan on, here’s why: Having a direct stream of air blowing on you can wick moisture away from your body and dry out your mucous membranes, Dr. Huh says.

Once your nose is irritated, it produces too much mucus. That’s because the mucin glands are working overtime to overcompensate and cover up any dry patches in your nasal passage, he says. This can cause swelling of the mucous membranes and lead to congestion.

During the winter, when the air is even drier and the heat is high, nasal congestion can get worse. Simply put, “our upper airways want to live in the Mediterranean,” says Dr. Huh.

4. It can make you more likely to get sick

When you frequently sleep with a fan on, your mucous membranes can dry out. And without the right amount of mucus, you become more susceptible to disease.

“Normally, our mucus provides a layer of protection preventing any type of irritant or organism from entering. But once dry, the mucus becomes very easily penetrable,” says Dr. Huh. Read: It’s easier to catch a cold.

To make matters worse, when your mucous membranes dry up and there’s little mucus to moisten the skin, you may also start to have cracks in your nose, Dr. Huh says. These small openings in the skin can become an entry point for bacteria and cause more inflammation.

To add insult to injury, that dry, cracked skin can also cause bad nosebleeds, he says.

Not only does sleeping with a fan weaken your nose’s defenses against possible infection, but it can also spread existing germs. If you share a room with someone who has a cold, a fan will blow some of the virus particles in your direction, says Dr. Huh. In other words, the current from a fan can carry a constant stream of insects while you sleep.

6. It can dry out your skin

We already know that blowing air from a fan can dry out your mucous membranes. But it can also dry out your skin, especially in cold climates with dry, heated indoor air, says Dr. Dedhia.

Remember that a fan wicks moisture away from your skin. It can even dehydrate you a bit, says Dr. Huh. This is because when you sleep you are essentially fasting (i.e. not drinking water), and using a fan just contributes to more fluid and moisture loss, he said.

7 ways to optimize your fan

Sleeping with a fan is bad for you in some contexts. But don’t worry: if you’re a big Fan fan, you can eliminate its negative effects by trying these tactics:

Regular cleaning, dusting, and vacuuming can reduce the amount of dust and dander in your home and reduce the number of allergens that fly by a fan. Don’t forget to wipe down the fan as well, as the blades also accumulate dust, says Dr. Dedhia.

However, cleaning alone will not solve the problem. “It doesn’t matter if you clean every day, there will always be dust,” says Dr. Huh.

2. Put a bowl of water in front of the fan

“It can help with the dehydration part,” says Dr. Huh. “You can blow moisture your way.” And in the summer, try adding ice cubes for a cooling effect.

3. Direct it away from your face

Dr. Huh recommends pointing a fan at your lower body. This way you are not blowing allergens and irritants directly into your upper airways.

“It’s ideal to keep a fan at least three to six feet away from the face,” says Dr. Dedhia.

5. Keep it on a lower setting

A strong fan will produce more allergens and be drier, says Dr. Huh. Conversely, a fan set to a low setting will likely do less damage this way.

Having a humidifier in addition to a fan will help circulate moisture and lessen the drying effect, Dr. Dedhia says.

7. Keep your window closed (if the air quality outside is poor)

If you live in a high-traffic area (or anywhere else with poor outdoor air quality), don’t sleep with your window open when you have a fan on, says Dr. Huh.

“I had a patient who had a bus idling outside her window and she had horrible symptoms, but when she closed the window she started to feel better,” he says.

Ditch the Fan and Try These Alternatives

For some people, like those with severe allergies, sleeping with a fan on can be more of a hassle than it’s worth. Rest assured, you can still doze off quietly. Just try these expert-approved alternatives:

1. Opt for air conditioning

When it comes to your upper airways, sleeping with AC is much better for you. Many air conditioners come with filters to block irritating pollutants, says Dr. Huh.

Although ACs do not aggravate your allergies, unfortunately they are more damaging to the environment. To reduce damage to the planet, keep your air conditioner on the lowest setting and at a reasonable temperature (i.e., don’t blow it out in arctic temperatures) and always use energy-saving mode .

2. Sleeping with fewer clothes

If you want to stay cool, sometimes the obvious solution is best: consider sleeping in your birthday suit, with fewer clothes or fewer blankets, says Dr. Dedhia. The best part? It is environmentally friendly and does not waste electricity.

3. Get a white noise generator

Your main reason for using a fan might be to drown out unwanted nighttime noise, especially if you live on a busy city street. Luckily, the roar of a fan isn’t your only option.

You can buy a white noise machine or use a white noise phone app, says Dr. Dedhia.

In fact, you don’t even have to pay a penny. “If you just go to YouTube, you can find six hours of white noise,” says Dr. Huh. Just report it on your phone and head off to dreamland.


Practicing good sleep hygiene — such as keeping a regular bedtime and dozing off in a quiet, dark room — can also help you get some sleep, according to the Mayo Clinic.

So how bad is it really to sleep with a fan on?

Whether or not sleeping with a fan on is bad for you depends on several factors. For allergy sufferers, this can significantly worsen symptoms. If you think sleeping with a fan is making your allergies worse, try without a fan for a week. If you feel noticeably better, you know your fan is a factor in your allergy flare-ups.

For allergy-free people, sleeping with a fan on is less likely to be a problem, as long as the air quality is good. “But if there are enough pollutants or irritants in the air, it doesn’t matter whether you are allergic or not, it will affect you,” says Dr. Huh.

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