Fast, Reliable Duct Repair & Sealing Across Simi Valley
We answer calls from Simi Valley homeowners seven days a week, and our trucks make the run up the 118 from our Los Angeles base in under an hour for scheduled appointments. If you’re in 93063, 93065, or the pockets up near the Santa Susana Pass, we’ve likely already worked on a house on your street. Ray Castillo has kept Bellows Air Duct & Vent Co. running since 1984 on one principle: show up when we say, quote the honest price before touching a tool, and stand behind the work for 90 days in writing. For duct repair and sealing in Simi Valley, that means understanding the specific problems this valley’s older homes face - brittle fiberglass duct board from the 1970s, flex duct sagging in crawlspaces that hit 120°F in August, and the unique ash-loading that follows every major wildfire. Call (844) 685-6342 for a free estimate. Most jobs finish in a single visit.
Why Bellows Air Duct & Vent Co. Is Simi Valley’s Preferred Duct Repair & Sealing Company
We’ve been serving Ventura County homeowners for over 42 years, and Simi Valley has always been a significant part of our route. The same families call us back because the work holds up. Our technicians are background-checked, uniformed, and equipped with camera inspection gear from Rotobrush and Abatement Technologies - we show you the inside of your ducts before we start and after we finish, so there’s no question about what changed.
Calls are answered by a live person, 24 hours a day. Not an app, not a voicemail tree. If your HVAC is blowing dust or smelling smoky after a wind event, you’ll talk to someone who can dispatch help.
Our pricing is disclosed upfront before any work begins. The number we give on the phone is the number on the invoice. We also honor a permanent 5% Senior and Veteran discount, and we offer $50 off any repair over $250.
We know Simi Valley’s neighborhoods. We’ve replaced sagging flex duct in crawlspaces near Sycamore Drive, sealed metal trunk lines in the original tracts off Cochran Street, and inspected duct systems in Wood Ranch homes after the Easy Fire sent ash through outdoor air intakes. That local familiarity means we diagnose faster and fix it right the first time.
Our Duct Repair & Sealing Services in Simi Valley
Duct Sealing
Leaky ducts steal 20-30% of conditioned air before it reaches your rooms. In Simi Valley, where summer highs crack 100°F and your AC runs hard for months, that’s money bleeding into your attic or crawlspace. Our Duct Repair & Sealing team pressurizes your system and maps every leak with a smoke pencil and digital manometer. We seal accessible joints with mastic sealant - the thick, fiber-reinforced compound that outlasts tape by decades - and replace deteriorated connections where needed. For homes near the 118 corridor with original 1970s ductwork, this single service often drops utility bills noticeably.
Flex Duct Repair
Flex duct is common in Simi Valley’s 1970s and 1980s builds, and it’s failing now. The plastic inner liner gets brittle after 40 years of heat cycling. Support straps sag. Critters get into crawlspaces. We recently repaired a duct system in a late-1970s home near the Santa Susana Pass, where the original flex duct had sagged and separated at the joints, pulling in ash and dust from the crawlspace. We replaced the deteriorated sections with new insulated flex duct and sealed every connection with mastic, restoring proper airflow and eliminating the musty smell that had plagued the homeowners for years. Most flex duct repairs in Simi Valley run $280-$550 depending on linear footage and access.
Metal Duct Repair
The older metal trunk lines in Simi Valley’s 1960s ranch homes were built to last, but the joints and seams weren’t. Decades of thermal expansion in 100°F-plus summers open gaps at elbows and takeoffs. We spot-weld separated seams, replace corroded sections, and seal every joint with mastic. For metal systems with extensive corrosion or improper original sizing, we’ll tell you straight whether repair or partial replacement makes more sense. No scare tactics. One honest price, shown before we start.
Duct Insulation
Uninsulated or degraded duct insulation in Simi Valley attics is a double penalty. You’re paying to cool air that warms up before it reaches the vent, and in winter, heated air loses temperature in cold attic spaces. We install new foil-faced fiberglass insulation or replace damaged flex duct with pre-insulated product rated for California Title 24 standards. This matters especially in Simi Valley’s inland valley bowl, where summer temperature swings between outdoor highs and attic lows can exceed 50°F.
Mastic Sealant Application
Mastic is our preferred sealant for Simi Valley’s aging systems. Unlike duct tape, which dries and fails in attic heat, mastic remains flexible and bonds to metal, fiberglass, and flex duct. We brush or trowel it into every joint, seam, and connection point, then verify with post-application pressure testing. For homes with original duct board along the 118 corridor, mastic sealing of accessible joints is often the most cost-effective improvement available short of full replacement.
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 Simi Valley
We stock parts and specify equipment from Rotobrush, Abatement Technologies, Aprilaire, and Honeywell - the same brands serious HVAC contractors use, not hardware-store knockoffs. For Simi Valley homeowners, that means faster turnaround. We don’t wait three days for a specialty fitting to ship from out of state. Our trucks carry insulated flex duct in standard diameters, mastic compound, mechanical fasteners, and replacement dampers. If your system uses Aprilaire media filters or Honeywell zone controls, we service those too. Camera inspection gear from Rotobrush lets us document condition before and after, so you see exactly what changed.
Common Duct Repair & Sealing Problems We See in Simi Valley Homes
- Brittle fiberglass duct board shedding glass fibers. Simi Valley’s legacy 1960s-1980s tract homes often have original fiberglass duct board that sheds glass fibers into the air when the liner breaks down, a problem rarely seen in newer neighborhoods like Wood Ranch or in neighboring cities with newer housing stock. Homeowners notice glittering dust on vents or experience increased allergy symptoms. We inspect with cameras and recommend repair or replacement based on liner condition.
- Flex duct sagging and separating at support points. Age plus valley heat turns flex duct supports brittle. The duct droops, kinks, or pulls apart at collars. This creates airflow blockages and opens entry points for the fine dust that blows through Simi Valley every Santa Ana season. We re-support and replace deteriorated sections.
- Joint separation in original metal trunk lines from thermal expansion. Simi Valley’s 100°F-plus summers cause repeated expansion and contraction in uninsulated metal ducts. Seams open, screws back out, and conditioned air escapes into attics. We re-seal with mastic and replace hardware where corrosion has weakened connections.
- Post-wildfire ash and smoke residue infiltration. After the Easy Fire burned directly on the ridgelines above Simi Valley residential streets in October 2019, local HVAC technicians found ductwork in homes with no structural fire damage nonetheless coated with fine white-gray ash and detectable smoke residue throughout the supply runs. This pattern is now well-known among experienced Simi Valley techs who treat post-fire duct inspection as a standard follow-up service after any nearby wildfire.
Pricing for Duct Repair & Sealing in Simi Valley, CA
We’re transparent about numbers because we’ve seen what bait-and-switch pricing does to homeowners who’ve already been burned once.
| Service | Typical Range in Simi Valley |
|---|---|
| Duct sealing (mastic, accessible joints) | $350-$650 |
| Flex duct repair/replacement (per run) | $280-$550 |
| Metal duct repair (spot welding, seam sealing) | $320-$680 |
| Duct insulation replacement | $400-$850 |
| Full system camera inspection with report | $150-$250 |
What moves you within these ranges: accessibility (crawlspace vs. attic), linear footage, and whether we can repair or must replace. Homes in older 93063 neighborhoods with original duct board often need more extensive work than 1990s Wood Ranch builds. We inspect with cameras first, then quote. The estimate is free. The price doesn’t change after we start. Call (844) 685-6342 for your specific quote.
Standing offers: $50 off any repair over $250. Free second opinion on any written estimate. $89 seasonal tune-up. Permanent 5% Senior and Veteran discount.
We Also Serve Cities Near Simi Valley
Our service area extends throughout Ventura County and the west San Fernando Valley. We regularly run to Simi Valley and the surrounding communities of Oak Park, Moorpark, Thousand Oaks, and West Hills. If you’re on the border between cities, call us - we likely already service your neighborhood.
Serving Simi Valley, CA - Our Local Coverage Area
We’re based in the Simi Valley 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 Simi Valley
It depends on liner condition, which we determine with camera inspection. If the fiberglass interior is intact and joints are sound, we can seal accessible connections with mastic and extend serviceable life. If the liner is breaking down and shedding fibers into the airstream - common in pre-1985 homes along the 118 corridor - replacement is the safer long-term solution. We give you the camera footage and an honest recommendation either way. Call (844) 685-6342 for a free inspection.
We inspect first with cameras to determine smoke residue depth. Light surface contamination in metal ducts often responds to thorough agitation cleaning with HEPA extraction. Deeper residue in porous fiberglass duct board, or systems with melted or warped components, requires replacement of affected sections. This post-fire pattern is well-documented in Simi Valley since 2019, and we treat it as a standard service, not an unusual request. Estimates are free - call (844) 685-6342.
Every three to five years for most homes, but annually if you live near recent burn zones or notice dust accumulation, uneven cooling, or rising energy bills. Simi Valley’s combination of aging housing stock, heavy dust loads from dry chaparral, and periodic wildfire ash makes proactive inspection worthwhile. We offer an $89 seasonal tune-up that includes basic leak detection. Call to schedule.
Yes, and it’s often the most cost-effective improvement for these systems. We access joints and seams, clean surfaces, and apply mastic sealant that remains flexible through decades of thermal cycling. If corrosion has weakened sections or original sizing is inadequate for modern HVAC loads, we’ll note that in our report. Most metal duct sealing jobs in Simi Valley run $350-$650 and finish in one visit.
Wood Ranch homes are newer, typically 1990s-2000s construction with more modern flex duct and better initial insulation. However, we still see age-related flex-duct sagging, joint separation, and accumulated debris from the valley’s heavy dust loads. The specific problems differ - you’re unlikely to face brittle fiberglass duct board liner breakdown - but inspection every few years still catches issues before they become expensive. Call (844) 685-6342 to schedule camera inspection for your Wood Ranch home.
Ready to fix your ducts? Call Bellows Air Duct & Vent Co. at (844) 685-6342 for a free estimate in Simi Valley. Most repairs are completed in a single visit, and every job is backed by our 90-Day Done Right Promise - in writing, no arguing, no paperwork if something needs attention.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Simi Valley since 1984.