Dry heating air irritates the respiratory tract: Four tips on how to increase the humidity in the rooms. According to the consumer advice center, the optimal humidity is 40 to 60 percent.
If the values are below this, the air is too dry, which can lead to irritated mucous membranes. If it is over 60 percent (over 50 percent in winter), the risk of mold increases. In the morning, when the humidity is at least 60 percent, you should definitely ventilate to remove moist air.