Fast, Reliable Duct Repair & Sealing Across San Jose
Duct repair and sealing in San Jose typically costs between $280 and $850 depending on the scope, with most residential jobs completed in a single visit. If your vents are pushing reddish-brown dust, your upstairs rooms won’t cool, or a smoky odor still lingers years after wildfire season, the problem is almost certainly leaks or damage in your attic ductwork. Call Bellows Air Duct & Vent Co. at (844) 685-6342 for upfront pricing and a free estimate.
We’ve been driving to San Jose from our Los Angeles headquarters for over 42 years, and we know the valley’s quirks. The 1950s tracts off Story Road, the retrofitted bungalows near Japantown, the hillside homes up toward Almaden - each has its own ductwork story. San Jose’s bowl-shaped geography, trapped between the Diablo Range and the Santa Cruz Mountains, creates conditions no coastal Bay Area city faces. Smoke, pollen, and valley dust accumulate with nowhere to escape, then bake into your ducts during summer attic temperatures that regularly top 140°F. Our Duct Repair & Sealing team treats this as routine, not a mystery.
Why Bellows Air Duct & Vent Co. Is San Jose’s Preferred Duct Repair & Sealing Company
San Jose homeowners call us because we’ve earned a reputation for showing up when we say and leaving the job finished. Our 90-Day Done Right Promise is stamped on every invoice - if something’s not right, we return at no charge with no paperwork to argue over. Ray Castillo, who leads our company, insists on it.
Our technicians are background-checked, uniformed, and equipped with camera inspection systems from Rotobrush and Abatement Technologies. We inspect every duct run before we touch it and again before we leave, so you see what we see. No claims without proof.
Calls are answered by a live person, 24 hours a day. Not voicemail. Not an app. A real person who can dispatch a technician to San Jose neighborhoods from Willow Glen to Evergreen.
We disclose every price before lifting a single tool. The number on the phone is the number on the invoice. No bait coupons, no changes at the door. That’s been our practice since 1984.
Our Duct Repair & Sealing Services in San Jose
Mastic Sealant
Mastic is the only sealant we trust for San Jose’s extreme attic conditions. Brush-on mastic stays flexible where tape fails, and we apply it to every joint, seam, and transition in your metal duct runs. In San Jose’s 140°F-plus attics, cheap foil tape dries and peels within a single summer. Mastic cures to a permanent, flexible bond that withstands decades of thermal cycling. We use professional-grade compounds from Abatement Technologies, applied thick enough to see, not thin enough to miss.
Metal Duct Repair
The original sheet-metal ductwork in San Jose’s 1950s-1970s tract homes was built to last, but the seams weren’t. We’ve replaced entire sections of corroded galvanized duct in East San Jose homes where Diablo Range soil fines had settled in low spots, forming an acidic sludge that ate through the metal from the inside out. Our metal duct repair includes custom-fabricated replacement sections, sealed with mastic and supported properly to prevent future sagging. In an East San Jose tract home near Story Road, we pulled decades-old metal ductwork coated in a reddish-brown film of Diablo Range soil and wildfire residue. The flex duct transitions had disintegrated, and we replaced them with sealed metal sections and mastic, restoring airflow and eliminating the burnt odor lingering since the 2020 SCU Lightning Complex fires.
Flex Duct Repair
Flex duct is common in retrofits and additions throughout San Jose, especially in the older neighborhoods near Naglee Park where central heating was added to bungalows decades after construction. Flex duct crushes, tears, and disconnects at the collar. We replace damaged flex with properly sized, insulated runs secured with metal straps and sealed at both ends. No sagging. No kinks. No air loss into your attic.
Duct Insulation
Unconditioned San Jose attics destroy duct insulation. The R-value of your insulation drops as it compresses, moisture-vapor barriers crack, and the conditioned air you’re paying to cool leaks into 140°F spaces before reaching your bedrooms. We install fresh, properly rated insulation on every repaired or sealed section, vapor-sealed and strapped to maintain performance. For homes in ZIP codes 95118, 95119, 95120, and 95121, this single upgrade often drops summer electric bills measurably.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in San Jose
We stock parts and specify equipment from Rotobrush, Nikro, and Abatement Technologies - the same brands serious HVAC contractors use, not the consumer-grade alternatives sold at big-box stores. For San Jose customers, this means faster turnaround. We don’t order and wait. Our trucks carry metal duct stock, flex duct in standard diameters, mastic compound, and replacement insulation so most repairs finish in one visit. Ray Castillo established this standard decades ago: if the part isn’t on the truck, we aren’t ready to work.
Common Duct Repair & Sealing Problems We See in San Jose Homes
- Smoke residue bakes into permanent duct film. San Jose’s valley-bowl geography traps Diablo Range wildfire smoke and agricultural pollen, which accumulate in attic ductwork and bake into a compacted film during 140°F+ summers, driving recurrent demand for Duct Repair & Sealing. Standard cleaning can’t remove it without first sealing the leaks that let it enter.
- Flex duct bends become debris traps. Smoke residue and pollen accumulate in flex duct bends, narrowing airflow and embedding odors that standard cleaning can’t fully remove without sealing leaks. The accordion ridges catch particles like a filter that never gets changed.
- Summer attic heat destroys seals and insulation. Summer attic temperatures above 140°F cause duct insulation to degrade and mastic seals to crack, leading to major air loss and particulate infiltration. Every summer makes the problem worse.
- Soil fines corrode metal seams from within. Diablo Range soil fines and construction dust settle in low spots of metal duct runs, forming a sludge that corrodes seams and requires full sealing or replacement. We find this in nearly every pre-1980 San Jose home we open.
Pricing for Duct Repair & Sealing in San Jose, CA
Here’s what duct repair and sealing costs in San Jose’s current market:
- Single leak seal (mastic, accessible joint): $280-$380
- Flex duct section replacement (up to 25 feet): $340-$520
- Metal duct seam repair and resealing (per section): $420-$650
- Full duct insulation replacement (typical 1,800 sq ft home): $680-$850
- Comprehensive duct sealing with post-repair camera verification: $720-$940
Costs run toward the higher end when attic access is limited, asbestos wrap is present on older ducts, or multiple corroded sections need replacement. We disclose your exact price before starting. Every repair over $250 qualifies for our $50 discount. Seniors and veterans receive a permanent 5% reduction. Call (844) 685-6342 for a free estimate with no obligation.
We Also Serve Cities Near San Jose
Our technicians regularly work in Campbell, Santa Clara, Milpitas, and Saratoga. If you’re in these communities, the same pricing, same 90-Day Done Right Promise, and same live-answer phone line apply. Duct Repair & Sealing in San Jose is our core valley service, and we extend coverage to every neighboring city without markup or delay.
Serving San Jose, CA - Our Local Coverage Area
We’re based in the San Jose area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Duct Repair & Sealing in San Jose
Smoke particles entered your duct system through leaks and are now embedded in the duct walls, especially in flex duct ridges and at disconnected collars. Standard air fresheners and even duct cleaning can’t remove this residue until the leaks are sealed. In San Jose, the 2020 SCU Lightning Complex fires and subsequent seasons deposited enough particulate in valley homes that we’re still treating it. Call (844) 685-6342 - we’ll camera-inspect your system and show you exactly where the smoke entered.
Yes, it’s often essential. The original sheet-metal ductwork in San Jose’s post-orchard boom homes was never designed for modern HVAC loads, and the seams have likely been leaking for decades. Sealing restores airflow, reduces energy waste, and prevents the Diablo Range soil and pollen infiltration that’s common in these neighborhoods. Most of our San Jose customers in 95118 and 95121 see immediate improvement in room-to-room temperature balance. Call for a free estimate - we’ll show you the leaks before you commit.
Small leaks grow. Attic air - 140°F in summer, full of insulation particles and rodent debris - gets drawn into your living space. Your HVAC system works harder, your filters clog faster, and the leaks expand as vibration and thermal cycling stress the seams. In San Jose’s climate, a minor leak typically becomes a major failure within two to three summers. We offer an $89 Seasonal Tune-Up that catches these problems early. Call (844) 685-6342 to schedule.
Carefully, with attention to the retrofitted connections. Many East San Jose bungalows had ductwork added during 1960s-1970s furnace conversions, creating mismatched metal-to-flex transitions and tight attic spaces. We use mastic sealant applied by hand in these confined areas, replace crumbling flex with properly sized runs, and support all metal to prevent sagging. Camera inspection before and after documents every sealed joint. We’ve done this work near Story Road and throughout the 95122 area for decades.
Yes, if the dust is coming from your attic ductwork. That reddish-brown color is characteristic of Diablo Range soil and baked wildfire residue - a combination we see almost exclusively in San Jose’s valley bowl. It enters through leaks, gets blown through your vents, and settles on furniture near the registers. Sealing the leaks stops the source. We also offer a free second opinion on any written estimate you’ve received elsewhere. Call (844) 685-6342 to discuss your specific situation.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving San Jose since 1984.