A hygrostat measures the humidity and can regulate ventilation in relation to the set value in% RH (ie% Relative Humidity)

The relative humidity should preferably be below 45%. This is normally only possible in winter, when we heat up the indoors. With a relative humidity of less than 45% the amount of house dust mites (HDM) is drastically reduced .
A low relative humidity also inhibits the growth of most molds.