Air Duct Mold Removal in Sunnyvale, CA

What duct mold actually means in a Sunnyvale house

Summer nights here cool off fast. The AC runs into the evening. Uninsulated metal boots sweat where they meet the register. That drip lands on dust, and dust feeds growth. In pre-1950 Peninsula homes with crawlspace runs, the underfloor humidity makes it worse. Eichler-type retrofits with added ducted heat pumps see the same thing at new attic boots.

First job is finding the water. Mold in a duct is a symptom. We look at the evaporator coil, the condensate pan, the drain line, and any boot with condensation staining. Clean the duct and ignore a plugged pan, and it comes back by next August.

Surface matters. Bare galvanized trunk can be cleaned and stays clean. Gray flex with a deteriorated liner cannot (the fiber is already shedding, and scrubbing it makes that worse). Same with fiberglass duct board plenums eroding at the cut edges. Those get cut out and replaced, not brushed.

We contain it, use HEPA collection, then remove the source. We do not fog a system and call it handled. We do not sell a coating over live growth.

If it is gray attic dust pulled through a disconnected return boot, say so. That is a sealing repair, not remediation.