RESOURCES
How often should air conditioning ducts be cleaned?
Technical article from the resource center.
There is no single frequency: it depends on what the inspection shows. Industry references work on periodic inspection and cleaning when the inspection justifies it, not on a fixed calendar.
High relative humidity and the lack of an off-season mean the system almost never dries out. Manufacturer maintenance intervals, written for installations that rest several months a year, fall short in these conditions.
The accessible sections are inspected with a camera, the condition is documented and, with that evidence, it is decided whether cleaning is due and when to inspect again. The report leaves the decision justified for whoever has to defend it.
To see how this applies to a specific installation: See what the inspection is like. Back to resources.