Proper ventilation is important: on the one hand, to maintain a good indoor climate and avoid headaches, and on the other hand, to prevent mold. While ventilation usually doesn’t cause any problems in summer, many people do it wrong in winter.
When there is “bad air” or “smells” in a room, many people open the window. But then it is often too late and a headache has already set in. To avoid this, many people simply leave the window open all the time in summer – but in winter there is often far too little ventilation due to the low outside temperatures.
Too much humidity and too much carbon dioxide lead to headaches
The idea behind it is to want to keep the heat in the apartment, especially with high heating costs. It is often not taken into account that adults exhale around a liter of water every night. According to the consumer advice center, during the day it is a total of six to twelve liters for a four-person household. The humidity quickly becomes much too high if there is no ventilation. This is perceived as unpleasant – and at some point mold develops. Not to mention, people also emit carbon dioxide when they exhale. If the CO2 content in the air is too high, you will also find the indoor climate unpleasant, become tired and get headaches.
“A comfortable living environment depends on the right ratio of room temperature and humidity: depending on whether the residents are sitting on the sofa or doing housework, this is at a temperature of 18 to 22 degrees Celsius and a relative humidity between 40 and 60 percent,” writes the consumer advice center on its website. For hygienic reasons and to maintain this indoor climate, you should completely replace the air three to four times a day and always ventilate immediately in the morning, after showering and after cooking.
Ventilate sufficiently even in winter using the 5×5 rule
In summer this can take a good 20 minutes – but if you leave the window open for that long four times a day in winter, you will be very cold during this time and will have a high utility bill at the end of the year. That’s why, according to the information portal FOCUS, the Window + Facade Association (VFF) recommends the following approach for the cold season:
– Outside temperature below 0 degrees Celsius: do not ventilate for more than five minutes at a time
– Outside temperature at 0-10 degrees Celsius: do not ventilate for more than ten minutes at a time
– Outside temperature above 10 degrees Celsius: ventilate for around 15 minutes at a time
If you are at home a lot, you should ventilate five times throughout the day: The “5×5 rule” can be used here, according to which you should ventilate five times in winter for a period of five minutes. If you are in the office during the day, you can limit yourself to ventilating the room three times – and if it is really too cold outside for the recommended ventilation time, you should ventilate not less often, but for shorter periods of time.
VFF: Ventilate when necessary – but only for as long as necessary
In summary, the VFF explains according to FOCUS: “You should ventilate when it is necessary and only for as long as necessary. In addition to your personal feeling, a hygrometer can help here. If the humidity is more than 60 percent, ventilation must be carried out.” If two windows are opposite each other, you should open both of them to allow optimal exchange of air and, if it rains, you should of course only open the windows through which it does not rain into the apartment. For people with hay fever, frequent ventilation in summer can be a real problem. If you don’t have a ventilation system with a filter, you should still ventilate the room because less pollen, grass and pollen get into the apartment than when the window is tilted. And the information platform co2online.de wants to know that cities tend to have the least amount of pollen in the morning and that pollution in rural areas is lowest in the evening. co2online.de doesn’t name a scientific source for this – but it’s probably worth a try.
Editorial team finanzen.net