Air Duct Sanitizing in Bodega Bay, CA

What does sanitizing actually do to a duct?

Short answer: it treats surfaces, not air. An antimicrobial fog or wipe-down kills what is living on the metal or liner. It does not remove debris. Sanitizing a duct still packed with rodent nesting or drywall dust just coats the mess. Cleaning comes first. Always. On coastal Bodega Bay jobs the real target is usually mold film on cold supply duct, where damp marine air meets a chilled metal surface.

Duct type decides what we can use. Bare galvanized trunk in a pre-1970 crawlspace tolerates a direct application. Insulated flex from 1980s attic tract work does not — the inner liner is porous, and soaked fiber stays wet. Deteriorating original wrap on old crawl runs is the same story. Sometimes the honest answer is replace that section, not treat it.

We check the return side before anything else. Undersized or leaking filter slots and plenums in older tract homes pull crawlspace and attic air straight into supply. Sanitize the supply, leave that leak, and the spores return within weeks.

Worth doing after rodent intrusion or standing water. Also after a humidity episode. Also after fire smoke, though ash is a cleaning problem first. Spring oak and grass pollen alone? Change the filter instead.