Ventilation sounds self-evident, but in practice, it is done too little in many homes. While we are increasingly insulating our homes to limit heat loss, letting in fresh air remains one of the most important things you can do for a healthy indoor climate.
What happens if you don't ventilate?
An enclosed space quickly accumulates a buildup of substances that you cannot see, but definitely notice. Consider:
- An increasing CO2 concentration due to breathing, especially in small, tightly sealed rooms like the bedroom
- Increasing humidity due to showering, cooking, drying laundry, and breathing
- Volatile organic compounds (VOCs) released from furniture, paint, and cleaning products
- Odors that linger instead of disappearing
Many people notice this in a stuffy feeling, difficulty waking up after sleeping, or a musty smell that just won't go away.
Ventilation is different from air purification or dehumidification
It is a common misconception that an air purifier or dehumidifier can replace ventilation. That is not the case: an air purifier filters particles such as fine dust and pollen from the air already in the house, but does not remove CO2 and does not supply fresh air. A dehumidifier lowers humidity, but does nothing about CO2 or a lack of oxygen-rich air. Only ventilation, via windows, vents, or a mechanical system, provides a real refreshment of the air with fresh air from outside.
How much ventilation do you need?
There is no exact figure that applies to every home, but as a guideline, you should air out your home briefly several times a day and, in addition, provide some form of permanent ventilation, for example through vents or a mechanical system that continuously moves a small amount of air. Bedrooms often require extra attention because the CO2 concentration there can rise quickly at night due to the small space and closed window.
Ventilating in winter
In winter, the temptation is great to keep windows and vents closed because of heat loss. Ventilating briefly and specifically, ten to fifteen minutes a few times a day, loses relatively little heat while still removing the accumulated moisture and CO2. Permanent ventilation via vents can in most cases remain open, even in winter.
Signs that you are not ventilating enough
- Fogged windows, especially in the morning
- A stuffy or heavy feeling when waking up
- A musty odor that persists despite cleaning
- Quickly returning condensation or damp spots
If you recognize any of these signs, that is often the easiest starting point: start by ventilating more structurally and effectively, and then see if additional measures such as air purification or dehumidification are necessary for specific problems that ventilation alone does not solve.