How do I know if I need new air ducts?
Look at the ducts themselves, and at how the air feels at your vents. Damage you can see, and airflow that has changed, are the two big clues.
- Ducts with a torn or missing outer jacket, and insulation showing.
- Ducts that sag, kink or are flattened.
- A duct that has come loose and blows air into the attic or crawl space.
- Chew holes or droppings on or inside the ducts.
- Dust blowing out of the vents when the system starts.
- No airflow through one vent or a few vents.
- A musty smell when the heater or AC turns on.
If you see even one of these, it is worth having the ducts checked.
Where are my ducts, and how can I look at them?
In most Bay Area homes they run through the attic, the crawl space, or both. You can often see part of them from the attic hatch or the crawl space opening with a flashlight.
Look without climbing in. Flexible ducts look like large round tubes with a silver or gray outer jacket. You are looking for tears, flattened sections, sagging runs and droppings. Don’t touch droppings, and never step between attic joists.
Can damaged ducts be repaired instead of replaced?
Patching a torn flexible duct with tape rarely lasts: the jacket keeps tearing around the patch, and the insulation underneath is often damaged too. A quick fix also doesn’t help if rodents have soiled the ducts or the runs are crushed in several places.
That is why we replace whole duct systems only, not single runs. Every run is new, connected and insulated at the same time, so no old, worn duct is left behind to fail next. We follow every run at the free inspection and photograph what we find.
When is replacement the better choice?
When the damage is spread across the system, when rodents have been in the ducts, or when the space is being opened up for other work anyway.
- Damage in many places: torn jackets, crushed runs and loose joints all over the attic or crawl space.
- Rodent damage: chew holes, nests and droppings on or inside the ducts.
- Ducts lying on the dirt: common under older homes.
- Other work in the same space: when the attic is being cleaned or re-insulated, or the crawl space cleaned, it is the easiest time to replace the ducts too.
What ducts do you install?
New flexible insulated ducts with a silver jacket. We install JPL insulated flexible ducts, UL 181 listed.
UL 181 is the UL safety standard for factory-made air ducts and air connectors, so a listed duct has been tested against it. When you compare quotes, it is fair to ask which brand of duct each contractor will install. Our compare your quote page lists what else to check.
Who should replace air ducts?
A licensed contractor. In California, the C-20 HVAC license classification covers duct work.
Our California contractor license #1149346 includes C-20 HVAC, and we are licensed, insured and bonded. You can look up any contractor’s license on the California Contractors State License Board website before you hire them.
What happens on duct replacement day?
Duct replacement is a one-day job. Please be home on the job day and clear breakable items, like pictures and vases, from the path to the work areas.
The crew covers the path from the front door to the work areas with drop cloths or plastic sheeting. The old ducts come out and are taken away with us. The new ducts are run, connected and supported to fit the height and layout of your space. The crew takes before and after photos and sends them to you.
Should I replace ducts at the same time as other work?
It often makes sense. New ducts can go in the same visit as attic cleaning, new insulation or crawl space cleaning, so everything is finished together.
In a hot attic, a radiant barrier cuts the heat shining down on the new ducts. Customers who book two or more services get 10% off (one discount per job). See attic cleaning and crawl space cleaning.
How long do air ducts last?
There is no single number. Ducts in a cool, clean space can last a long time; ducts in a hot attic, or under a house where rodents live, wear out much sooner.
Condition matters more than age. That is why we look at the ducts themselves at the free inspection, instead of guessing from the age of the house.
Will new ducts cut down on dust?
They can, when the dust comes from torn ducts pulling in attic or crawl space air. New ducts with sound connections close that path.
Dust from inside the house, from carpets or a clogged filter, is a separate issue, so change the filter regularly either way.
What we see on real jobs
On duct jobs around San Jose, Fremont and Mountain View, the old ducts usually show a mix of:
- Torn outer jackets with the insulation hanging out.
- Runs crushed flat or sagging onto the attic floor or the soil.
- Joints that have come apart.
- Chew holes and droppings from rodents.
See air duct replacement for how we do it, and weak airflow from your vents if some rooms barely get air. Book a free inspection or call us, and get a written quote the same day.