Damage caused by excessive humidity and improper ventilation in storage rooms, offices, and apartments not only leads to high costs but is also unhealthy and unsightly. The widespread belief that moisture comes from outside is generally incorrect. In fact, moisture in the home is generated by evaporation, particularly in the kitchen and bathroom. The use of highly insulating building materials significantly impairs air exchange, which can only be adequately ensured through active ventilation. Therefore, controlling the indoor climate is important for healthy living. The device measures the indoor climate and warns of mold growth and condensation through adjustable minimum and maximum alarm values.