Chicagoland Air Duct, a leading HVAC company in the Chicago area, reminds customers that the summertime is the best time to clean air ducts. Once customers turn on their furnaces in the fall, the air inside the ductwork will start circulating again, and any potential dust, dirt, or pollen can contaminate the interior air, according to the company. Ducts and the air inside them should be cleaned by professionals with years of experience.