HVAC Duct Cleaning in San Jose, CA

Why San Jose ducts load up with dust

Most of it is attic air, not room air. Older homes here use panned joist returns, open framing cavities pressed into service as return duct. Those joist bays were never sealed. The blower pulls attic dust and insulation fiber through them, along with rodent droppings. Add a 1-inch filter in an undersized slot and air bypasses the edges entirely. The dust lands in the trunk line, then redeposits when the system runs.

The second cause is remodel work. Constant kitchen and bath projects across Willow Glen and Naglee Park throw drywall silt into open registers. It is fine and gray. It clings to flex liner. Late-summer wildfire soot loads systems again. Spring pollen is a third layer.

Duct age decides the method. 1950s–60s galvanized trunk takes brush agitation fine. Brittle gray flex from the 1970s–90s does not. A rotary brush can tear the inner liner and dump fiber into the airstream. That duct wants contact vacuuming and, often, replacement instead. Any paper-backed or suspect insulation on an older unit stops the job until it is tested.

Realistic interval in this valley is three to five years. Shorten it after a remodel or heavy smoke. Also shorten it if pets and attic ducting combine. Crawlspace runs deserve a separate look for mold.