HVAC Duct Cleaning in Sunnyvale, CA

Why Sunnyvale ducts load up in the first place

Most of it starts in the attic. The 1950s-70s tracts here run galvanized trunk with round branch takeoffs, later patched with insulated flex. Tight attics crush those flex runs. Boot-to-register joints work loose and dump conditioned air into the insulation. The return then pulls attic dust back through the house. Old cloth-tape joints on sheet metal dry out and leak. Hall return filter slots are often undersized, so air bypasses the filter edge and loads the blower wheel and evaporator coil instead.

The cleaning itself is mechanical, not a spray. Negative pressure at the trunk, agitation inside each run, register by register, with the rest of the system blocked off. Blower wheel and coil get attention separately. Dirty coil fins hold more than most duct interiors do.

Some ducts should not be cleaned. Gray flex liner that is already shedding fiber will shed more under a brush. Fiberglass duct board plenums erode at cut edges. Rodent-contaminated crawlspace runs in foothill-adjacent homes need replacement and remediation, not a vacuum.

Pull one register and look at the boot yourself. Gray streaking on the ceiling around a supply means leakage, not dirt. Most homes here go three to five years; pets, grassland exposure, nearby construction or smoke intrusion shorten that. Re-insulation, re-roof and remodel jobs always warrant a look.