Air Duct Sanitizing in Ventura, CA

Does sanitizing actually fix a musty duct smell?

Sometimes. Often not. The odor usually starts at the return side, not the supply. Ventura's marine layer keeps return air damp. Add a long AC off-season and fiberglass liner near the coil and plenum grows surface mold. Spraying an antimicrobial over wet liner buys weeks. The liner has to dry, or be cut out and replaced, before any treatment holds.

So the first step is finding the moisture. Uninsulated metal boots sweat in crawlspaces. Pre-1960 under-floor trunk-and-branch runs with failed external wrap pull soil and damp straight off the crawlspace. Hallway and closet platform return plenums framed from drywall or wood leak unfiltered wall-cavity and attic air. Seal those and the smell often leaves on its own.

Rodent contamination is a different job. Droppings and nesting in attic flex are removed and the chewed jacket replaced, not fogged. Same with wildfire ash loaded into attic runs (that is a cleaning problem first).

We inspect before quoting because the honest answer is sometimes no. Metal duct with rust at the seams, within a mile or two of the beach, may be past treating. If the liner is saturated or the flex is crushed, sanitizing is money spent on a surface that will smell again by next summer.