When is duct cleaning appropriate?

When is duct cleaning appropriate? Although the value of regular duct cleaning remains questionable, the U.S. Environmental Protection Agency (EPA) and indoor air specialists agree that duct cleaning (or, in some cases, duct replacement) is appropriate in the following circumstances: • Permanent or persistent water damage in ducts   • Slime or microbial growth observed in ducts   • Debris build‐up in ducts that restricts airflow • Dust discharging from supply diffusers   • Offensive odors originating in ductwork or HVAC component. BEFORE hiring a duct cleaning contractor, make sure you can answer “YES” to all of these questions: 9 Are there known or observed contaminants in the ductwork? 9 Have you confirmed the type and quantity of contaminants based on testing or observation? 9 Are the contaminants (or their by‐ products) capable of entering occupied spaces? 9 Have you identified and controlled the source of the contaminant?   9 Will the duct cleaning effectively remove, inactivate, or neutralize the contaminant? 9 Have you considered other options, such as removal of affected ductwork? 9 Is duct cleaning the only (or most effective) solution? In all cases, duct cleaning should be undertaken only after the source of the contaminant has been identified and controlled. Otherwise, the problem will not go away. For instance, the water source