Air duct cleaning in San Jose is worth paying for in a handful of situations and a waste of money in others. Clean the ducts after a remodel, after rodents or insects have been in them, or when dust and debris actually blow out of the supply registers. Don’t expect it to fix allergies, a musty smell from a wet coil, or household dust that really comes from leaky return ducts and a poor filter. Here is how to tell which case you’re in.
When it’s worth doing
- After construction or a remodel. Drywall dust, sawdust and plaster grit get pulled into the returns whenever the system runs during the work. This is the most common good reason for a cleaning.
- Signs of pests. Droppings, nesting material or a dead-animal smell from a register mean cleaning, after the entry point is found and sealed.
- Debris coming out of the registers. Dust puffs, insulation bits or grit when the system starts mean something inside is loose or dirty enough to matter.
- Visible growth after a moisture problem. Growth on hard metal duct surfaces can be cleaned once the moisture source is fixed. In fiberglass duct board or duct lining, the affected section usually has to be replaced instead.
- A house with an unknown history. Moving into a home where years of pet hair are packed into the returns is a fair reason to start clean.
When it usually isn’t
- As a yearly routine. Ducts don’t fill up the way a filter does. With a decent filter and sealed returns, most stay serviceable for years.
- Dusty grilles. A grey film on the face of a register is normal and says little about the inside of the duct.
- Allergy symptoms. There’s no solid evidence that duct cleaning alone prevents health problems. We won’t tell you otherwise.
- A musty smell. Look first at the drain pan, the indoor coil and the condensate line. Clean ducts won’t stop a smell that a wet part keeps producing.
- Old flex duct near the end of its life. Brushing brittle flex can tear the inner liner. If a run is crushed, torn or disconnected, replacing it is the better use of the money.
A five-minute look before you call
Unscrew one supply register and shine a flashlight inside. A thin layer of dust is normal. Clumps, debris, droppings or anything that looks damp are worth a visit. Then pull the filter. If it is caked, bent, loose in its slot or missing, that alone explains a lot of household dust, and changing it costs far less than a cleaning. Our filter guide covers how often to change it.
What a full cleaning covers
A proper job treats the whole system, not just the vents you can see. The ducts are put under negative pressure with a high-powered collection vacuum, and each supply and return run is worked with rotating brushes or air whips so loosened dirt travels to the collector instead of into your rooms. Registers and grilles come off and are washed. The return plenum and the blower compartment are cleaned too, because that is where much of the dirt ends up. You get before-and-after photos of the inside of the ducts. Sanitizing products are an option, used only when there’s a reason for them and never in place of cleaning.
Older San Jose ducts: clean, seal or replace?
Many San Jose houses are several decades old and still run original or second-generation ducts through the attic or crawlspace. Years of summer attic heat dry out flex duct jackets and tape until joints come apart. What makes sense depends on what we find:
| What we find | What usually makes sense |
|---|---|
| Sound metal ducts with heavy dust or remodel debris | Cleaning |
| Sound ducts, leaky joints at the plenum or register boots | Cleaning plus sealing the joints |
| Flex duct crushed, torn or disconnected | Replacing those runs, cleaning the rest if needed |
| Wet or moldy duct board or lining | Fixing the moisture, then replacing the affected sections |
| Return duct drawing air from the attic or crawlspace | Sealing the return before anything else |
The leaky return deserves its own mention. It pulls dusty attic air into the system downstream of the filter, so the house gets dusty again soon after any cleaning. Sealing it is often the single most useful repair on the list, and our article on HVAC in older homes covers the duct layouts these houses tend to have.
Dust, pollen and smoke
Dry summers bring fine dust, spring brings pollen, and smoke days leave soot that the filter catches first. After a heavy smoke season, change the filter before you think about the ducts. If soot still shows on the registers once the filter is fresh, that is the time to look inside. For air that stays dusty after the ducts are clean, better filtration or a whole-home air purification system does the ongoing work that a one-time cleaning can’t.
What it costs
Most duct cleaning jobs run $299–$599. The number of supply and return runs, attic or crawlspace access and how dirty the ducts are move the price within that range. You see the price before work starts. The duct cleaning cost guide has more on what changes the number, and if the air in your home seems off for reasons you can’t pin down, read about poor indoor air quality.