A building’s HVAC system is designed to perform several tasks: filter, cool, heat, humidify, dehumidify, pressurize, and/or exhaust. Each of these tasks affects indoor air quality. For example, if incoming air is not properly filtered, excessive dust from the outdoors is drawn into the building. If supplied air is not conditioned or heated satisfactorily, occupants may experience thermal discomfort. If supplied air is not dehumidified appropriately, excessive relative humidity levels may promote microbial growth.