At the library, is it important that the environment is not too moist. Large variations in temperature and humidity can cause condensation or cracking in the books. Organic materials contain micro-organisms that can be brought to the strife of moisture and heat. Even microfilm benefit from a dehumidified climate, then it is an easy way to preserve them. A dehumidified climate also do so there is no risk of mold, it improves indoor air quality while avoiding the costs of heating, ventilation and air conditioning after closing.