Fast, Reliable Duct Repair & Sealing Across Altadena
Duct repair and sealing in Altadena typically runs $280-$750 depending on whether we’re sealing joints with mastic or replacing fire-damaged fiberglass duct board, and most jobs are completed in a single visit. If your home is in ZIP 91001 or 91003 and your HVAC was running during the January 2025 Eaton Fire, your ductwork likely pulled sub-micron ash and soot deep into the system. That contamination doesn’t stay put. It recirculates. Call (844) 685-6342 for a free camera inspection and honest upfront pricing before we lift a single tool.
We’ve been driving the winding roads above Altadena Drive for over 42 years. Our technicians know the difference between a 1920s Craftsman bungalow off Mariposa Street and a mid-century ranch up toward Loma Alta Park, and we know what kind of ductwork each one hides. Altadena’s foothill position against the San Gabriel Mountains means your system works harder than flatland Pasadena homes just a few miles south. Santa Ana winds push chaparral dust and ash straight into outdoor intakes. After the Eaton Fire, that problem became acute. We’re here to fix it right, back it in writing for 90 days, and never need to be called back.
Why Bellows Air Duct & Vent Co. Is Altadena’s Preferred Duct Repair & Sealing Company
Altadena homeowners don’t call us for flashy trucks or coupon gimmicks. They call because their neighbor on Mendocino Street told them we showed up when we said we would, showed the price before we started, and left a camera recording of clean ductwork behind us. Our Duct Repair & Sealing team has rebuilt trust with foothill residents one job at a time, especially since the fire.
Ray Castillo built this company in 1984 on a simple standard: one honest price, shown before work starts, backed by a promise stamped on every invoice. That 90-Day Done Right Promise means if it’s not right, we return at no charge. No paperwork to file, no argument. We’ve answered calls with a live person 24 hours a day since before cell phones existed, and we still do.
Our background-checked, uniformed technicians carry professional-grade equipment from Nikro, Honeywell, and Aprilaire - the same brands serious HVAC contractors specify for their own homes. Most Altadena repairs finish in one visit because our trucks are stocked for the actual duct systems we find here: degraded fiberglass board, collapsed flex runs, and metal trunks that need real mastic work, not tape.
Our Duct Repair & Sealing Services in Altadena
Duct Sealing
Leaky ducts in Altadena don’t just waste energy. After the Eaton Fire, they pull contaminated attic air and ash-laden crawlspace air straight into your living space. We seal with mastic compound at every joint, collar, and penetration - not foil tape that peels in our summer heat. A typical duct sealing job in Altadena runs $280-$450 for a single system, and we camera-verify every seal before we leave. Homes near the mountain front see the worst leakage from pressure differentials during Santa Ana events.
Flex Duct Repair
Oversized flex runs were common in Altadena’s 1960s ranches and later additions. They sag, they trap particulate, and they collapse when wind pressure hits your outdoor unit. We replace damaged flex with properly sized runs secured at proper pitch so condensation drains and debris doesn’t pool. Typical flex replacement in Altadena: $180-$340 per run. If the flex was pulling fire ash, we inspect the full line - contamination doesn’t respect the section you can see.
Metal Duct Repair
This is where we spend most of our time in Altadena’s older homes. Original metal trunks in Craftsman bungalows rust at seams, separate at collars, and were never designed for the particulate load a wildfire generates. We cut out failed sections, fabricate replacement metal to fit, and seal with mastic at every joint. Metal duct repair in Altadena typically runs $340-$620 depending on access and extent. On a Craftsman bungalow near Loma Alta Park, our crew sealed a degraded fiberglass duct board trunk line that had pulled in heavy ash loads from the Eaton Fire. We replaced the failed section with metal ductwork, applied mastic sealant at all joints, and installed a Rotobrush brush-cleaning system to restore the HVAC to fire-safe operation.
Duct Insulation
Uninsulated or degraded duct insulation in Altadena attics costs you year-round. Summer attic temperatures hit 140°F and winter nights drop below freezing at this elevation. We install foil-faced fiberglass insulation at R-6 or R-8 value, sealed with mastic at all seams. Typical insulation wrap or replacement: $220-$480. Proper insulation also prevents condensation that feeds mold in our variable foothill climate.
Mastic Sealant Application
Mastic is the only sealant we trust for Altadena’s conditions. It remains flexible through temperature swings, fills irregular gaps tape can’t reach, and creates a permanent air barrier. We brush-apply mastic at every joint, saddle tap, and register boot on repair jobs. For full system sealing, mastic application runs $280-$450. It’s labor-intensive. It costs more than tape. It lasts decades longer, and we stand behind it.
Air Leak Repair
Fire ash finds every gap. We pressurize your system and use smoke testing to locate leaks invisible to the eye, then repair with metal fabrication or mastic sealing as appropriate. Air leak detection and repair in Altadena: $260-$520. We show you the camera footage before and after. That’s not a sales tactic. It’s how we prove the work.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
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 Altadena
Our trucks carry parts and materials from Honeywell, Aprilaire, and Nikro - brands that hold up in real conditions, not just on spec sheets. Honeywell media air cleaners integrate with repaired duct systems to capture residual ash particulate that standard filters miss. Aprilaire humidifiers and dehumidifiers help stabilize Altadena’s wide indoor humidity swings, protecting fresh mastic seals from premature cracking. Nikro’s HEPA-filtered collection systems keep our work contained during repair, critical in homes still sensitive to airborne contaminants after the fire. We don’t order parts from a warehouse three counties away. We stock what Altadena homes actually need.
Common Duct Repair & Sealing Problems We See in Altadena Homes
- Fiberglass duct board degrades and leaks after fire ash exposure. The binder resins in older duct board break down when saturated with alkaline wildfire ash. We’ve pulled sections in ZIP 91001 that looked intact from the outside but crumbled at a touch. Full replacement with metal ductwork is the only lasting repair.
- Oversized flex runs trap fine particulate and collapse under Santa Ana wind pressure. Altadena’s exposed foothill position means outdoor units take direct wind hits. Flex duct between the unit and foundation wall is the failure point. We replace with metal where possible and properly support flex where it’s unavoidable.
- Heavy-duty openers and springs on detached workshop doors fail when duct repair involves accessing overhead duct runs in outbuildings. Altadena’s acreage properties often have detached workshops with independent HVAC. Our technicians are equipped to access overhead ductwork safely, including in structures with non-standard door hardware that complicates ladder and lift positioning.
- Return air pathways pull contaminated crawlspace and attic air. Many Altadena bungalows have panned joist returns or unsealed chases that bypass filters entirely. We seal these pathways with solid metal and mastic, not patchwork that fails in the next wind event.
Pricing for Duct Repair & Sealing in Altadena, CA
We’re square dealers. The price we quote is the price on the invoice. No bait coupons, no changes at the door.
| Service | Typical Range in Altadena |
|---|---|
| Duct sealing (mastic, single system) | $280-$450 |
| Flex duct repair/replacement (per run) | $180-$340 |
| Metal duct repair (section replacement) | $340-$620 |
| Duct insulation (wrap or replace) | $220-$480 |
| Air leak detection and repair | $260-$520 |
| Post-fire full system assessment with camera inspection | $89-$150 (credited toward repair) |
What moves the number: access difficulty (crawlspace vs. attic vs. finished basement), extent of fire damage, whether we’re sealing existing sound ductwork or replacing contaminated material, and how many supply/return branches need attention. We offer $50 off any repair over $250, a free second opinion on any written estimate you’ve already received, and a permanent 5% senior and veteran discount. Call (844) 685-6342 for an exact quote - estimates are free, and we’ll show you the camera footage so you understand exactly what needs doing.
We Also Serve Cities Near Altadena
Our Duct Repair & Sealing in Altadena crews also respond to calls in Pasadena, La Cañada Flintridge, South Pasadena, and San Gabriel. Each community has its own ductwork character - Pasadena’s flatter terrain sees different particulate loading, La Cañada’s newer construction has different failure modes - but our 90-Day Done Right Promise and upfront pricing travel with us to every job.
Serving Altadena, CA - Our Local Coverage Area
We’re based in the Altadena 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 Altadena
Even homes that survived structurally intact have HVAC systems contaminated with sub-micron ash and soot that entered ductwork while the system ran during the firestorm. Standard cleaning doesn’t remove embedded particulate from degraded fiberglass duct board, so repair and sealing often requires replacing fire-damaged sections with metal ductwork and applying fresh mastic at all joints. Call (844) 685-6342 for a camera inspection - estimates are free.
Craftsman bungalows in Altadena often retain original or early-retrofit duct systems with degraded fiberglass duct board and oversized flex runs that were never engineered to handle fine wildfire particulate. The alkaline ash breaks down binder resins in fiberglass board, and the tight crawlspaces and partial basements common in these homes make access difficult for anything but experienced technicians. We replace failed sections with metal and seal properly for the long term.
Yes. Altadena’s acreage properties often have detached workshops with independent HVAC and heavy-duty overhead door hardware that complicates access to overhead duct runs. Our technicians carry equipment for non-standard access situations and can repair or replace ductwork in outbuildings while maintaining containment for any residual ash. We’ll assess the full system, not just the main house.
Absolutely. Systems that ran during or immediately after the Eaton Fire pulled contaminated air through every component, depositing a distinct grey-black fine-ash coating inside supply ducts all the way to the registers. This pattern is invisible from return grilles but confirmed on camera inspection, and it degrades seals, insulation, and duct board throughout the system. Filter replacement alone cannot address it - targeted repair and sealing of damaged sections is required.
We specify Honeywell media air cleaners, Aprilaire humidity control components, and Nikro HEPA-filtered collection equipment - the same brands serious HVAC contractors use in their own installations. These hold up to Altadena’s particulate loading and temperature swings, and we stock them locally for same-day repair completion. Call (844) 685-6342 to discuss what’s right for your system.
Ready to get your Altadena home’s ductwork sealed right and backed in writing? Call (844) 685-6342 for a free estimate. We’ll show you exactly what we find, quote one honest price before we start, and stand behind the work for 90 days with no paperwork and no arguing. That’s how we’ve done it since 1984.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Altadena since 1984.