Your Austin Air filter has been designed to last up to 5-years under normal residential use. If your Austin Air cleaner is used in rooms with unusually high concentrations of tobacco smoke, sawdust, soot, chemical vapors and/or odors, your Austin Air fi lter wil l need to be replaced more often . In these circumsta nces, you should replace your filter once your Austin Air cleaner ceases to emit clean, odorless air. If the odor of the highly concentrated contaminant is present exiting the Air Output Vent, then it is time to replace your filter.