Can An Aircon Make A Person Sick If Left Running While Sleeping At Night?

 October 25, 2020

By  Cool Man

The truth is that some nights are just too hot for you to sleep without turning ON the air conditioner. The heat can make a person feel restless and disturbed while trying to sleep. As a result, such a person will spend hours tossing and turning. Let us not forget that sleep plays a huge role in our overall well-being just like food and water.

Remember, without food and water, our body will shut down and die. This is a similar fate that will happen when a person fails to sleep for more than four days. Lack of sleep will first affect a person’s mental abilities (such as fail to concentrate and increased forgetfulness). It then escalates by creating physical health issues (heart-related diseases, developing type II diabetes, and much more). All of the above are life-threatening conditions.

However, the million-dollar question is: is sleeping the Aircon ON at night make you sick? Or what are the health risks associated with leaving an Aircon ON overnight?

Researching on this topic will yield different results. You will find some experts saying leaving an Aircon ON overnight while sleeping will make a person sick is a myth. On the other hand, some say that it is common sense that there are a few disadvantages to a person’s wellness. To be on the safe side: it is wise to follow scientific proof.

Below are five reasons you should avoid turning your Aircon ON before going to bed.

1. Our Body’s Core Temperature

Have you ever ask yourself why we need to cover ourselves with a blanket to sleep through the night? Well, that is because the body needs to maintain its core temperature for one to have a lovely night. If this temperature drops, a person will require an extra cover to maintain the temperature. Therefore, keeping the Aircon running through the night will lower the body temperature even further – even when one is covered and the night is warm.

When the core body temperature drops, the minor thing that will happen is suffering from disrupted sleep. The worse thing being bodily function interference.


It is healthier to set the Aircon heat control to a higher temperature than you would during the day. It is wise to have a room ambient temperature of about 77 degrees Fahrenheit or 25 degrees centigrade. This is the right or ideal temperature to boost or imp-rove sleep during the night. During warm nights, it is recommended to avoid lowering the temperature but rather take a cold shower and then sleep.

2. Body Fluids Drying Out

Did you know that cold dries our body’s fluids? As such, if you wake up in the morning and notice that your skin, nasal passages, throat, and mouth are dry, then your body experienced a cold night. This may be as a result of running the Air conditioner at a lower temperature through the night. According to health science, dry throat, mouth, and nose make the body susceptible to illnesses.


For this reason, it is recommended to set the air conditioner to 90% humidity while sleeping. If your heating and cooling unit does not have a humidity setting, then consider investing in a quality humidifier, which should be run in conjunction with the heating unit.

3. Bodily Sleep Functions

When a person sleeps, the body redirects its energy and resources to other functions that are paused during the day when a person is active and awake. Examples of such functions include boosting immunity, replacing worn-out cells, replacing torn muscles, and healing injured areas. For this reason, when sleep is disrupted or influenced, these bodily functions can be affected, resulting in low immunity, long-healing periods, and so on.

Another research shows that lowered temperatures may be affected. For example, the production of important hormones, which are often released during the night while sleeping may be impaired.


If you are struggling to sleep during the night because of the summer heat, then consider turning ON the Aircon; but set the sleep function. This is a setting that will automatically turn the air conditioner OFF after a particular time. Doing this will not affect your core body temperature through the night, which will help you have a good quality night sleep.

4. The Body’s Thermal Adaptation

What is a Body’s Thermal Adaptation? Well, this simply refers to the body’s ability to adapt to specific cold or hot temperatures. For example, if you take hot showers every day, then your body has become used to the hot showers (temperatures). This is a fact that also applies to how you use the Aircon during the night. As such, if you run the air conditioner all day and all night, then your body will lose its ability to adapt to varying temperatures.

Remember, our bodies are designed to regulate its own temperature by opening and closing pores, sweating, and even increasing or decreasing blood circulation. Therefore, if you continuously sleep within the same cold temperature range during the night, the body will lose its ability to self-regulate temperature.

As such, a mildly warm day during spring may seem too hot for you to handle, which may cause the body to perspire unusually. You may also find yourself taking off your coat in temperatures where others would find uncomfortably cold.


If you must set an Aircon temperature in your bedroom, then consider setting variable temperature settings. This means that sometimes you have to set it at a higher temperature than you would normally do. Also, do not turn it ON unless necessary.

5. Hygiene

It is highly important to ensure the air conditioner is well maintained, and the filter is cleaned and replaced regularly. An air conditioner’s filter can be a breeding ground for bacteria and other harmful microorganisms like fungi and mold. Spores from these microorganisms can be circulated by the heating and cooling units. This could lead to serious health issues and, in some cases, lead to serious health problems like Legionnaires’ disease.


Although running a clean and well-maintained air conditioner does not pose any health risks, it is always wise to take precautionary steps. Only through precaution will you be able to get the most at protecting your overall well-being.

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