How often should I clean my Ductwork?

In the commercial environment it is going to depend upon many factors affecting the building. Is there high usage of the space? What is the space used for? What is the desired level of cleanliness for the space? All of these questions and more should be discussed and a plan can be implemented to best suit the needs for the specific facility. Some homeowners who are sensitive to their indoor environment have us clean their ductwork annually. Most people should have the ductwork in their home cleaned every three years.