The Indoor Air Quality – VOC control senses the level of Volatile Organic Compounds (VOCs) in a space and automatically adjusts the ventilation rate to the space by increasing or decreasing the speed of the fan based on the level of VOCs present. Ventilating based on the VOC concentration assures the space will not be over or under ventilated. Up to 10,000 unique VOCs exist, and Greenheck’s VOC sensor reacts to all of them.