Moisture Control is the process of controlling indoor moisture levels that is important to protect occupants from adverse health effects and to protect the building. Proper ventilation is a part of a moisture control strategy. So what causes moisture? Moisture condenses into water droplets when warm, humid air contacts a cool surface. Cooking, bathing, drying clothes, washing dishes and other everyday activities add moisture to the air. Some heating appliances, including unvented natural gas or kerosene models, also increase the moisture inside your home.