is sleeping next to an ac dangerous

Is Sleeping Next to AC Dangerous? – Air Conditioning At Night

Is sleeping next to an air conditioner (AC) dangerous? If you have an air conditioner in your bedroom, you might wonder about this question. Can you sleep while the AC is running? In this article, we’re going to find out everything about the dangers of using air conditioners while you sleep.


Quick Answer: Yes, sleeping next to an AC is dangerous. The temperature drop air conditioners cause can harm your health, especially when you sleep. Additionally, the noise level of air conditioners harms your sleep quality. If you sleep next to an AC every night, the noise level will significantly impact your alertness, memory and brain-performance (really dangerous when you’re driving). On top of that, many ACs (especially in hotels) distribute bacteria and mould.

But this quick answer is just scratching the surface of the problems. Let’s find out more about why sleeping next to an AC is dangerous.

Is Sleeping Next to AC Dangerous?

I know you want to sleep in a cool room right now rather than feeling as if you were in the amazonian jungle. However, you need to take a look at what air conditioners can do to you while you sleep. Think twice whether you want to use one.

Sleeping next to an air conditioner becomes really harmful to you because of three major issues they cause. These are:

  • temperature change
  • noise level
  • bacteria and mould spores

The Temperature Change of ACs is Dangerous during Sleep

ACs are great for cooling rooms. But when you spend an entire night (8 hours!) sleeping next to one, the first issue you’ll instantly notice when you wake up is that your neck muscles became stiff.

The reason you will wake up with a stiff neck, which is very uncomfortable, is a simple law of physics. When it’s hot your body expands. When it’s cold, it contracts. That’s a mechanism of your body that protects you against harsh temperature changes. When it’s cold your body (and especially your muscles) contract so they can maintain your current body temperature more effectively.

Your Neck Muscles Become Stiff

Now, think about what happens to your body when your muscles are contracted for the whole night just because you sleep next to an air conditioner? Exactly, you will feel stiff when you wake up. Your whole body will be stiff, however, your neck muscles will stiffen up to a level where it can even become painful. The reason is that your neck muscles are mostly fine, small muscles that precisely rotate and tilt your head. Your neck muscles are the “biggest loser” when it comes to sleeping next to an AC.

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If you sleep next to an AC regularly, the stiffness of your body will increase up to a point where only a physician and massages can relieve it.

Your neck hates air conditioners. You’ll regret it the next morning.

On top of that, you will not only hate yourself for sleeping next to a running air conditioner because of your neck pain but also because your sleep quality suffered. I bet you can imagine that sleeping with tense muscles has an impact on how well you sleep and how refreshing your sleep is. Sleep relaxes you and restores your whole body. But what kind of relaxation do you get when your whole body is tensed up.

You’ll Sleep in Dried Out Air

To cool down your room, air conditioners suck up all the moisture in your room. When you sleep next to a running AC, it’s basically the same as sleeping in a dry desert, except it’s not that hot. When the air is dried out, your throat might become sore as it’s used to moisturized air. On top of that, ACs increase the chance of you have a cough the next day. There are just so many health issues with ACs, but these two are enough to get the point:

If you don’t want to risk a sore throat, better leave the AC turned off.

The Noise Level of AC Harms Your Sleep

ACs generate noise. Good ACs have the motor that produces most of the noise outside of the building. However, that doesn’t mean they are completely silent. Usually, ACs generate blowing wind-sounds, similar to fans. Oftentimes, you don’t even notice the noise. But when you turn off the AC, you are surprised how quiet it is. That happened to me very often. We notice AC noise only subconsciously. Which makes them a hidden danger to your sleep quality.

According to a study, even small noise levels have a significant impact on your sleep. Scientists compared the sleep quality of people who sleep in complete silence to that of people who sleep in noise environments (as with turned on ACs). As a result, those who slept in a noisy environment slept significantly worse. Even when the noise levels aren’t that loud and noticeable.

Noise Levels Destroy Your Sleep Quality

That does not only apply to ACs, but to all noise sources. For example street traffic, music and loud neighbours. Personally, I live in a small flat in the city centre with noisy neighbours and lots of street traffic. I found that the most effective solution to that is using earplugs. Here’s a list of the ones I recommend: Best Earplugs For Sleeping – My Top Picks

If you didn’t use earplugs up until now, here’s one thing I need to say to you.

You need earplugs.

They come in really handy, especially when you’re travelling.

Regarding ACs, the worst ones are those who switch on and off over and over in order to regulate the temperature. That might not sound bad. Why should it be bad? But you will notice the change in noise every time the AC turns on and off. It will wake you up over and over.

Dust and Bacteria in Air Conditioners are Dangerous

For some people, especially those with breathing issues like asthma, ACs are actually relieving. However, that stops as soon as your AC starts gathering bacteria and mould spores. The problem with ACs is that they suck up moisture from the air in your room. But some ACs seem to fail to blow the moisture outside. Instead, they gather the moisture, which creates a perfect breeding location for bacteria and mould spores.

When you turn on your AC, it will blow out some of the bacteria and distribute it in your room. And on top of that, it will keep circulating the infected air in your room. When you breathe in bacteria from an AC, you’ll definitely have a stuffy nose, a cold or even a temperature the next day you wake up.

NOTE: Not all air conditioners are infected. Especially not when you take care of yours. However, you have no control over the air conditioners in a hotel. You will need to be more careful with them.

If Sleeping with an AC is Dangerous – How Else Can You Keep Room Cool?

If we sum up everything that you’ve previously read, we can say that you should not sleep next to a turned-on air conditioner. It’s just not worth the risks. But what should you do instead? How can you cool your room otherwise? Here are some ideas you can use.

Air Your Room instead of Using Air Conditioning

This is the most obvious one, I know. Airing your room is a much safer option than using the air conditioning, as only clean and moisturized air will come in from outside. This works especially well in spring, autumn and winter. In these times of the year, you can simply tilt your window during the night. But pay attention that it doesn’t get too cold. Just like when you sleep next to an air conditioner, your muscles will tense.

My recommendation is, therefore, that you power-air your room before you go to sleep. Open your windows as much much as you can for 15 minutes. To improve the results, I use a fan and place it in front of my open window so it blows fresh air in. That comes in pretty handy if your room has only one window and air would come in rather slowly. Then close it and leave it closed for the night. You’ll have a cool room with fresh and clean air and you’re ready to sleep.

But what can you do in the Summer?

During the summertime, it becomes difficult to air your room in the evening, because its still hot outside. Never open your window when it’s hot outside! It’ll only make things worse. What you can do now is something similar to power-airing, but with your air conditioner. Let’s call it power-cooling. Turn it on for 15 minutes before you go to bed so your room cools down. As soon as you go to bed, you must shut off the air conditioner!

The best about power-cooling is that you will be able to fall asleep in a cool room but without all the negative side effects of sleeping next to an air conditioner. No infected air is swirling around, your muscles won’t tense (because the room will slowly get warmer during the night) and you won’t get a cold.

Power-Cool your room: Turn the AC on for 15 minutes before you go to bed.

Minimize Bad Effects by Using Just Slight Temperature Settings

If you, for some reason, need an absolutely stable room-temperature during the night, power-cooling is not for you. The room will slowly get warmer during the night. It’s not a big deal but maybe you don’t like that. Then the best you can do is to leave the AC on, but only with light temperature settings. Don’t go any lower than 3 degrees cooler than the outside temperature.

That will minimize the noise levels during the night and also keep the temperature and humidity relatively safe. However, power-cooling is a way better and healthier way.

What about using a Fan at night?

Please never use a fan when you sleep. Fans usually have significant noise levels that will destroy your sleep. Additionally, when you sleep next to a running fan, you are constantly exposed to blowing wind.

The constant airflow will “push away” the layers of warm air that lie on your skin. Your body will then think it’s cooler than it actually is and starts to fire up your body temperature to compensate it. This will make you sleep worse as your body can not focus on refreshing yourself and preparing you for the next day.

It needs to spend a lot of energy just for keeping your body temperature up. You will wake up tired and groggy and you won’t feel refreshed at all.

Is Sleeping Next to AC Dangerous? – The Outline

Sleeping next to an air conditioner is dangerous and comes with many risks and health issues. And on top of that, it will degrade your sleep quality. That means you will wake up feeling tired and groggy. If you want to have a good night of sleep, you need to overcome the urge to use air conditioning at night. In the long run, you and your body will feel much better and you’ll become sick less.

If you sleep with a running AC, you risk getting a cough, a sore throat, a stiff and painful neck and bad sleep quality. You’ll just feel bad the next day.

A better idea is to air your room before you go to bed. In the summertime, you can also power-cool your room with your AC by turning it on for 15 minutes before you go to bed and then shutting it off. That cools down your room but minimizes the risks that you would otherwise face if you would leave the air conditioner running.

If you want to learn how to optimize your sleep quality so you can fall asleep better and wake up refreshed and energized every day, check out all the other sleep improvement articles on this page.

Also, I’m always happy to hear from you in the comments! Share your experience and your opinion with me!

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