A Thermostat Humidistat is a device that measures and controls relative humidity in an enclosed space. It is typically used in commercial buildings, such as workplaces and schools, to regulate the indoor environment and promote occupant comfort. The device helps maintain optimal temperature and humidity levels, helping to protect furnishings, electronics, paper documents, and other items from damage caused by excess moisture or drying out. It also helps reduce the spread of airborne illnesses, improving air quality and promoting better health outcomes.