In winter, most people’s priority is to try to save energy as much as possible. In order not to waste the heat from the radiators, they try to entrench the house, preventing the slightest draft. They inspect the walls and ceiling to the millimeter, make sure that the windows and doors are properly closed to optimize the use of heating. All these precautions are commendable. But do not forget that it is essential to ventilate your interior daily. Excessive confinement is detrimental to both your health and your home.
Do you wonder how to ventilate the house efficiently? The real question to ask yourself: how long should windows be left open in winter? The answer is here.

Ventilate the house – Source: spm
Should you ventilate your house in winter?
Although the outside temperatures are lower in winter, this does not imply that the interior of the house should not be ventilated. It’s certainly quite understandable to want to save energy and gas by insulating your windows. But lack of air can cause a lot of damage. Between the accumulation of dust and bacteria, sensitive and allergic people can suffer. Having a completely sealed space is actually a great way to reduce energy bills. But a poorly ventilated interior is very bad for your health: to prevent the air from being contaminated with toxic particles, it is essential to ventilate the house, even in the dead of winter.
Also read: Leave this product overnight. In the morning the windows will be dry: an economic tip against condensation
Why ventilate the house in winter? 3 reasons
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Get rid of allergens
Although the flowering season is not yet close, the house is full of household allergens that can cause serious respiratory problems. In addition to the dust mites that colonize your carpets and bedding, your lungs also have to deal with chemicals from cleaning sprays or hair strewn all over your pet. Generally speaking, allergy sufferers often experience a worsening of symptoms in winter due to poor ventilation.
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Fight frequent colds
When the heating season is in full swing, the air in the house becomes very dry. Radiators tend to remove moisture from the air, thus drying out the mucous membranes in the nose and mouth. As a result, your body struggles to fight off viruses and bacteria that try to enter your immune system. Dry and poorly ventilated air is very often responsible for flu and colds during this period.
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Prevent the growth of bacteria and mold.
Finally, when you keep your interior airtight, you contribute to the inevitable growth of viruses, bacteria, and mold. Without fresh air at home, germs multiply in the air and on all surfaces. Even using a humidifier and air purifier, you still need a source of fresh air to remove the abundance of CO2 in your home.

Rainy weather – Source: spm
How long should the windows be left open?
So how often should the house be ventilated in winter, without wasting energy?
Also read: Why do grandmas always put tea bags on their windowsills?
Generally, the ideal is to open the windows at least 10 minutes a day. If you live in a small apartment, you should keep the windows open for at least 15 minutes. For houses or apartments facing busy streets, it is best to ventilate the interior early in the morning before 9 am and late at night after 10 pm to minimize contamination. It also favors the ventilation of your kitchen that is constantly plagued by smoke and various odors.
Also, be sure to lower the temperature inside the house. When cold air comes in through the windows, we tend to believe that more energy is necessarily needed to heat living rooms. This is a false calculation: to preserve your health, the ideal temperature should remain around 18°C, with the exception of the baby’s room where the room should be heated to 22°C. But, in other spaces, by reducing the thermal value of the house, you will not need to use the large-capacity boiler. Therefore, this will prevent you from having higher power consumption.
Also read: Mold around windows: how to get rid of it