Fast, Reliable Duct Repair & Sealing Across West Hills
Most duct repair and sealing jobs in West Hills run $280-$750 for standard sealing work, with flex duct replacement reaching $1,200-$2,800 depending on attic access and linear footage. We’re typically on-site in West Hills within 90 minutes of your call, and most repairs finish in a single visit. Call (844) 685-6342 for a free estimate with upfront pricing before we start.
We’ve worked in West Hills since the mid-1980s, back when the area was still filling in with the ranch and split-level homes that define its streets today. Our technicians know the difference between a home off Roscoe Boulevard near the 118 and one tucked against the Santa Susana Pass on the western edge - the wind exposure, the attic temperatures, and the duct systems are not the same. That local knowledge matters when we’re crawling through a 140°F attic in July, tracing a collapsed flex duct from 1974 back to its source.
Why Bellows Air Duct & Vent Co. Is West Hills’s Preferred Duct Repair & Sealing Company
We’ve served West Hills homeowners for over 42 years, and our reputation here was built on jobs done right the first time - backed by our 90-Day Done Right Promise in writing, not just spoken. Ray Castillo has led this company since its founding in 1984, and our office still answers calls with a live person 24 hours a day, including holidays.
West Hills customers tell us they chose us after a discount operator quoted one price by phone and doubled it at the door. We don’t work that way. Our Duct Repair & Sealing team shows you the camera footage of your actual ductwork before we quote, and the number we give is the number on the invoice. No bait coupons, no scare tactics, no price changes after we start.
Most of our West Hills calls come from the 91307 and 91308 ZIP codes, with response times averaging under 90 minutes during business hours. Our technicians are background-checked and uniformed, and they carry the equipment to complete most repairs - including flex duct replacement and full mastic sealing - without a return trip.
Our Duct Repair & Sealing Services in West Hills
Duct Sealing
Sealing is the right fix when your ducts are structurally sound but leaking conditioned air into attics or wall cavities. In West Hills, we see this constantly in homes built between 1965 and 1985, where original tape seals have dried and failed after decades in extreme attic heat. We seal with mastic compound or aerosol-based duct sealant - the only methods that survive Santa Ana wind pressure events and the temperature swings of a West Hills attic. A typical whole-system sealing in West Hills runs $450-$750 for an average 1,800-square-foot home.
Flex Duct Repair
West Hills homes built in the 1960s through 1980s often still have original flex duct with fiberglass inner liners that have simply reached end of life. The inner liner collapses under negative pressure, creating hidden restrictions that drive up your electric bill and starve rooms of airflow. Standard sealing cannot fix a collapsed liner. We replace damaged sections with new insulated flex duct, secure all connections with mechanical fasteners, and seal with mastic. Sectional replacement in West Hills typically costs $180-$340 per run, with full system replacement ranging $1,200-$2,800.
Metal Duct Repair
Some West Hills homes, particularly those with later additions or custom builds near Bell Canyon, have galvanized metal ductwork. Metal ducts don’t collapse like flex, but they corrode at seams, separate at joints, and transmit noise. We repair separated seams, patch corrosion, and reinforce weak points. Where metal has failed extensively, we often transition to insulated flex duct for better thermal performance in West Hills’s hot attic environment.
Duct Insulation
Original insulation on West Hills duct board and flex duct has frequently degraded after 40-60 years in attics that exceed 140°F. Bare or thinly insulated ducts lose 20-30% of conditioned air before it reaches your rooms. We reinsulate with formaldehyde-free fiberglass wrap or replace with pre-insulated flex duct, depending on the condition of the underlying duct structure. This is often combined with sealing work for a complete thermal upgrade.
Mastic Sealant Application
We specify mastic - a thick, fiber-reinforced compound - for all West Hills sealing work. Tape fails. Mastic doesn’t. In the high-vibration, high-temperature, high-wind environment of a West Hills attic, mastic is the only sealant we trust for long-term performance. We brush or trowel it onto every joint, seam, and penetration, then verify with camera inspection before we close the attic.
What happens when you call
- 1
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 West Hills
We stock parts and specify equipment from the brands that serious HVAC contractors trust: Rotobrush for mechanical duct cleaning and prep work, Abatement Technologies for HEPA containment and post-fire remediation, and Honeywell for UV air purification and control accessories. For West Hills homeowners dealing with residual wildfire contamination, we source Aprilaire media filters with MERV 16 ratings to capture fine particulate that standard filters miss. Our trucks carry inventory for same-day completion on most standard repairs - no waiting for parts to ship to the Valley.
Common Duct Repair & Sealing Problems We See in West Hills Homes
- Original duct board insulation delaminates in 140°F+ West Hills attics. The fiberglass facing separates from the duct board core, creating condensation pockets inside the duct wall that breed mold. We find this in roughly half the pre-1980 homes we inspect in the 91307 ZIP code. Repair requires section replacement, not sealing.
- Santa Ana winds drive fine chaparral dust through loose seams. Standard foil tape dries and lifts within months of application in West Hills’s wind-exposed locations. Only mastic or aerosol-based sealing creates a bond that survives these pressure events. We see this failure mode most often on homes near the Santa Susana Pass.
- Post-2018 wildfire soot condensate prevents mastic adhesion. The dark, oily residue our technicians find on West Hills duct interiors requires HEPA-rated mechanical cleaning and specialized primer before any sealant will bond. A standard compressed-air blow-out leaves enough residue to guarantee seal failure within a year.
- Original flex duct liners collapse under negative pressure. The spiral wire support in 1970s flex duct corrodes, and the inner liner sags into the airstream. Homeowners report weak airflow and high bills. The restriction is invisible from outside the duct. Camera inspection confirms it, and sectional replacement is the only permanent fix.
Pricing for Duct Repair & Sealing in West Hills, CA
We believe in one honest price, shown before we start. Here’s what duct repair and sealing costs in the West Hills market:
| Service | Typical Range in West Hills |
|---|---|
| Spot duct sealing (mastic, up to 5 joints) | $280-$450 |
| Whole-system duct sealing | $450-$750 |
| Flex duct section replacement (per run) | $180-$340 |
| Full flex duct system replacement | $1,200-$2,800 |
| Metal duct repair (seam/joint work) | $220-$480 |
| Duct reinsulation (per run) | $150-$290 |
| Post-fire remediation cleaning + sealing prep | $380-$650 additional |
Factors that affect your specific price: attic accessibility (tight truss spaces take longer), extent of wildfire residue requiring pre-cleaning, number of duct runs, and whether we need to coordinate with your HVAC contractor for air handler access. We offer $50 off any repair over $250, and our $89 Seasonal Tune-Up includes a basic duct inspection that often catches problems before they become expensive. Seniors and veterans receive a permanent 5% discount. Call (844) 685-6342 for a free estimate - we’ll show you the camera footage and give you the exact number before any work begins.
We Also Serve Cities Near West Hills
Our Duct Repair & Sealing in West Hills service area extends to neighboring communities including Canoga Park, Woodland Hills, Calabasas, and Chatsworth. Each area has its own ductwork challenges - from the older hillside homes of Calabasas to the dense tract housing of Canoga Park - and we adjust our approach accordingly. Wherever you are in the western San Fernando Valley, we bring the same upfront pricing, camera-verified results, and 90-Day Done Right Promise.
Serving West Hills, CA - Our Local Coverage Area
We’re based in the West Hills 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 West Hills
Partial repair is often possible if the outer insulation and inner liner are still structurally intact. We replace individual collapsed or torn sections and seal the remaining sound ductwork with mastic. If the inner liner is extensively delaminated or the spiral wire support has corroded through, full replacement is the only fix that lasts. Call (844) 685-6342 for a free inspection - we’ll show you the camera footage and give you an honest assessment.
Yes - the oily soot condensate prevents sealants from bonding and continues to off-gas odor when your system runs. We clean with HEPA-contained mechanical agitation and apply a primer before any sealing work. Standard duct cleaning without this fire-specific protocol leaves residue that guarantees seal failure. We responded to a 1978 ranch near Bell Canyon where the homeowner reported high electric bills and weak airflow. Our inspection found the original fiberglass duct board had disintegrated at the attic transitions, and late-2018 Woolsey Fire residue coated the interior. We replaced the damaged sections with insulated flex duct, sealed all joints with mastic, and installed a Honeywell UV air purifier to control residual smoke odor.
Absolutely. Attic temperatures in West Hills routinely exceed 140°F in summer, which destroys standard foil tape within one to two seasons and accelerates the breakdown of low-grade sealants. We specify fiber-reinforced mastic rated for 200°F continuous exposure, and we verify adhesion with a post-application camera inspection. The material costs more than tape. It also doesn’t fail.
Yes - the Santa Susana Pass funnels Santa Ana events directly into West Hills with higher velocity than the interior Valley experiences. Wind pressure at roof penetrations and loose access panels forces unfiltered air through any gap, overwhelming standard tape seals and depositing chaparral dust and ash inside your system. Mastic sealing at all joints, plus secure mechanical fastening of flex duct connections, is the only defense we’ve found that holds up.
Camera inspection tells the story. If the metal is sound with separated seams or small corrosion spots, sealing and spot repair is sufficient. If we find extensive corrosion, holes larger than a quarter, or separated sections that have pulled away from the main trunk, replacement of those sections is necessary. Metal duct in West Hills homes often fails at the joints first - the constant expansion and contraction from 140°F attic cycles works fasteners loose over decades.
Ready to stop losing conditioned air to your attic? Call (844) 685-6342 for a free estimate on duct repair and sealing in West Hills. We’ll show you exactly what your system looks like inside, give you one honest price before we start, and back our work with the 90-Day Done Right Promise - in writing, no paperwork if you need us back.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving West Hills since 1984.