The average cost for air duct cleaning can range anywhere from $500 to $1000. The amount depends on the size of the home and the complexity of the air duct system. For smaller homes, the cost may be as little as $400, however in many cases, the price reflects the quality of service. Many air duct cleaning companies will also offer extra services such as anti-bacterial sprays or chemical treatments to reduce mold. If there is not a known problem of mold, these extra services may be unnecessary wastes of money.