component. BEFORE hiring a duct cleaning contractor, make sure you can answer “YES” to all of these questions:

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