Commercial dryers are much larger than their residential counterparts and therefore do not need to have their vents cleaned as regularly. At average usage levels, you would expect to have your dryer vents cleaned approximately every 1-2 years. Clean air ducts are the foundation for good indoor air quality. Homeowners and business owners want to breathe clean indoor air for themselves, their guests, employees, and customers. Over several years, air ducts can also become contaminated with mold, fungi, and bacteria, as well as dust. Routine HVAC doesn’t remove them. Proper removal with equipment like Rotobrush’s air duct cleaning machines and systems is one way to improve indoor air quality.