Sleeping With The Fan On: Why It's A Bad Idea

When temperatures remain high after nightfall, many people have no other solution than to leave a fan on all night near their bed. Even without considering the electricity consumption of this device, this trick to cool down is not without its drawbacks. We will explain why it is a bad idea, especially for a certain category of people.

The electricity consumption of the fan is not the main problem.

As heatwaves and periods of extreme heat have become common in France during the summer, many French people have gotten into the habit of leaving a fan on all night near their bed. In the absence of air conditioning at home, this solution helps to cool the bedroom atmosphere and can aid in falling asleep.

If you are among those who have chosen a fan over an air conditioner, you are probably wondering if this device consumes a lot of electricity at night. On this point, sleeping with the fan on near your bed will not significantly impact your electricity bill. Of course, it depends on the model you use, its electrical power in watts, and its energy efficiency (rated from A+ to G), as well as the price per kilowatt-hour indicated in your electricity contract.

However, you don't need to engage in complicated calculations because the French Environment and Energy Management Agency (ADEME) has assessed the cost of using a fan to cool a room during the night. According to ADEME, this usage results in an increase of only €5 per month on average on the final bill, for all types of fans combined.

The impact of the fan on health is more problematic.

If you have heard that sleeping with the fan on is not a good idea, it is not for financial reasons. The main problem lies rather in the impact of this device on the health of sleepers.

Fans have the particularity of continuously circulating the ambient air. However, the indoor air in homes often contains a cocktail of substances potentially aggressive to the airways, such as dust, pollen, mold, mites, and other indoor pollutants emitted by aerosols and cleaning or DIY products.

Fans also have the effect of drying out the ambient air, which dehydrates the upper airways, skin, and eyes. Since the use of this device impacts the ENT (ear, nose, and throat) sphere, it is not uncommon to wake up the next morning with a stuffy nose and sticky eyes.

Finally, if you direct the airflow directly onto your body, you also risk catching a cold or waking up with muscle stiffness such as a stiff neck or lumbago depending on the area of your back exposed to the ventilated air.

Some people are more at risk than others.

Due to the potentially harmful effects of the fan on the body, sleeping with this device on near you is not a good idea, especially for allergic or asthmatic individuals.

If you suffer from one or more allergies, be aware that having a fan on all night can cause the following symptoms:
• repeated sneezing fits.
• watery eyes.
• a runny nose.
• throat itching.
• breathing difficulties.

For the most sensitive individuals, exposure to ventilated airflow for several hours can lead to rhinitis, bronchitis, conjunctivitis, or even an eczema flare-up, as air ventilation facilitates the penetration of allergens into the body.

A few good habits can help reduce risks.

If you have no other solution than a fan to cool your bedroom in the summer, remember the right practices for using this device and minimize health issues:

• regularly clean the blades of the device to remove dust.
• avoid directing the airflow towards your face or back.
• aim the device at your feet and place it far enough from you so that you do not receive air directly on your skin.
• set the device to medium power to reduce the risk of muscle cramps and the noise that could disturb your sleep.
• humidify the atmosphere by placing a bottle of ice water in front of the fan.

This last tip has the dual advantage of increasing the feeling of freshness and preventing dryness of the skin, nasal mucous membranes, and eyes.

Note: another device called an air cooler works on this principle. It offers a good compromise between a fan and air conditioning because it does not consume too much energy and can lower the ambient temperature by 3 to 4°C without drying out the air.