Air Duct Cleaning in San Mateo, CA

Partly, and it's the single most common call we get in San Mateo between November and March. Fog pulling through the San Bruno gap keeps crawlspaces damp for months, and the older downtown and San Mateo Park bungalows sit on raised crawlspaces where sheet metal runs stay cold. Moisture condenses on that metal, and any settled dust film on the inside becomes something mold can grow on. Cleaning removes the dust layer the growth feeds on, which usually cuts the smell down. But if the crawlspace itself is wet, has no vapor barrier, or the duct insulation is soaked, the smell comes back. We'll tell you which one you're dealing with rather than just cleaning and leaving.

Two patterns. On the 1920s–30s stucco and Spanish-revival homes near downtown, the house often started with a gas floor or wall furnace and had forced-air added later. The supply runs got installed, but the return path was an afterthought, often one undersized grille doing the work of a whole system. That starves the blower, pulls air through gaps instead of the filter, and loads the ducts with dust faster than they should. On the hillside split-levels and the 1960s–70s builds up toward the Highlands and the west side, it's attic flex instead: crushed runs, sagging bellies that collect debris, and taped joints that let go over time. Different fixes, so we look before quoting.