General statements on fixed ventilation times are difficult in most cases. This is because these values do not take into account actual moisture loads, local conditions or the number of people in the room. However, these factors are important and play a decisive role in determining when ventilation should take place. After all, the proportion of carbon dioxide, for example, increases more quickly when there are more people in a room and thus more CO₂ is exhaled. The air is quickly "used up." Uncomfortable feeling, tiredness or even headaches are the result.
In addition to normal metabolic processes, indoor air also emits pollutants such as volatile organic compounds (VOCs) from carpets and furniture. These air pollutants should also be removed regularly.
Factor number of persons: From when must be ventilated?
In our first test, we checked the air quality with our air-Q air measuring device in a 25 m² room. In doing so, we conducted the experiment with 1, 2, 3 and 4 people. We looked at when the air-Q detected a limit exceedance of the measured values and recommended to ventilate.
The curve of our evaluation clearly shows that the more people there are in the room, the shorter the interval until recommended ventilation. While the air-Q only recommends airing after 80 minutes if there is only one person in the room, the warning message appears after just under 40 minutes if there are two people, after half an hour if there are three people, and after about 25 minutes if there are four people.
The difference in air consumption between three and four people in the room is rather small. In both scenarios, the air-Q air meter strikes after about 25 to 30 minutes. Between one and two people, on the other hand, a significantly larger difference is noticeable: Here, the time data is halved from 80 minutes with one person to 40 minutes with two people in the room.
The important thing here is that the airing must be repeated. If there are three or four people in the room, it should be ventilated every 20 to 30 minutes. If there are two people in the room, it is sufficient to air the room every 40 minutes, and if there is one person in the room, it is recommended to air the room every 80 minutes.
Factor room size: From when must be ventilated?
In our second test, we varied the room size instead of the number of people. During different test runs, we examined the air quality in rooms with the following sizes: approx. 10, 20, 30, 40 and 50 m². There were always two people in the rooms. Here, too, the air-Q air measuring device showed us when to ventilate.
The measured values make it clear that in small rooms the air is consumed much sooner and must be ventilated. In a room of about 10 m², the air-Q indicates that the recommended limit value has already been exceeded after ten minutes. In a 20 m² room, the air-Q recommends ventilating after about 30 minutes. In a 30 m² room it is sufficient to open the windows every 50 minutes and in a 40 m² room every 65 minutes. In a 50 m² room, the air quality lasts the longest. Here it is sufficient to provide fresh air every 80 minutes.
Conclusion
Our tests show that the ventilation frequency depends very much on the factors number of people and room size. We were surprised by the fact that we felt that the limit values were exceeded very quickly. Accordingly, you should ventilate much more frequently than you think and pay particular attention to this in small rooms. Of course, this does not only apply to your private rooms, but also to small offices, meeting rooms or classrooms. These rooms usually have dimensions of 30 m² and should be aired accordingly frequently.
(Contributed image: Jun from Getty Images Pro/ canva.com & self-editing)
