Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
That "$99 whole-house special" is a bait ad - the real number appears once they are in your hallway, or the "clean" is a shop-vac at the register. We photograph the inside of your ducts before and after instead.
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After
Before
After
Before
AfterFast, Reliable Duct Sealing Across West Covina
We seal ductwork in West Covina homes where the Santa Ana winds have already done their damage. Our crews dispatch from the Los Angeles office and roll to West Covina with mastic, metal tape, and camera gear sized for the post-WWII ranch homes that dominate this city. If your registers blow dust after a wind event, or your bedroom never reaches the thermostat setting, the ducts are likely leaking conditioned air into the attic or crawl space. Call us at (361) 326-5060 and we’ll price the sealing in writing before any work starts.
West Covina sits in the San Gabriel Valley downwind of the Colby Fire burn scar, so late-summer and fall Santa Ana winds push ash and fine soot straight into HVAC returns. That ash is alkaline. It pulls moisture from the air and cakes onto galvanized duct interiors in a way coastal salt air does not. The combination of ash and humidity is why duct sealing here often has to happen before microbial growth in the ducts can be corrected. We’ve learned this from years of opening up systems in the neighborhoods south of the 10 and east of the 60.
Why Hollis Air Duct Cleaning Is West Covina’s Preferred Duct Sealing Company
We’ve been part of the Garrison Partners family since 2004, and our Duct Sealing in West Covina crews follow The Garrison Standard on every job: arrive inside the quoted window, price in writing, complete the work by the book, leave the site clean. West Covina homeowners know what to expect because we tell them before we arrive.
Our technicians are background-checked and uniformed. You know who walks in before they get there. The 365-Day Done Right Promise covers every sealing job in writing. If the work fails within a year, we return and make it right at no charge, including a free second visit. No negotiation, no runaround.
Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues, no waiting until Monday to schedule. Dispatch and scheduling are coordinated from our Los Angeles office, but the crews serving West Covina live and work locally. They know the difference between a 1962 ranch off Azusa Avenue and a 1978 split-level near the Eastland Center, and they know both likely have original ductwork that needs more than a quick tape job.
We were called to a ranch-style home near the 10 in West Covina after a September Santa Ana event left a visible layer of black grit in the return register. When we dropped a camera inspection into the return side, we found the original galvanized trunk had pinhole leaks at the seams and the flex run to the back bedroom had collapsed insulation, so we sealed the trunk seams and replaced the damaged flex before running the Rotobrush through it. The homeowner told us the dust film on the furniture dropped noticeably within a week.
Air Duct Sealing in West Covina
Air Duct Sealing in West Covina means closing the gaps, seams, and disconnections in your HVAC distribution system so the air you paid to heat or cool actually reaches the rooms. In a typical West Covina home built between 1950 and 1980, we find original galvanized steel trunk lines with failing seam seals, early flex duct runs with degraded insulation, and plenum connections that have loosened from decades of thermal cycling. The goal is simple: pressurize the living space, not the attic.
Most West Covina homeowners call us after noticing hot or cold spots, dust accumulation, or a spike in their energy bill. Others call after a Santa Ana wind event leaves black residue on return registers. In either case, we camera-inspect first, then seal what needs sealing and replace what has failed beyond repair.
What We Seal and What We Replace
We seal trunk line seams with mastic rated for HVAC applications, not hardware-store duct tape that dries and fails in two years. We replace collapsed or torn flex duct with new insulated flex sized to the original airflow calculation. If the galvanized trunk has rusted through at the seams, we cut out the damaged section and fabricate a replacement in place. The price is written before we start.
Camera Inspection Before Sealing
We run a camera through every accessible duct before sealing. In West Covina’s older housing stock, we’ve found deteriorated interior insulation, rodent damage, and previous patch jobs that trapped moisture. Sealing over these problems locks them in. We show you the footage, explain what needs sealing versus replacement, and price each line item separately.
Duct Sealing Services in West Covina
Duct Sealing Services in West Covina cover the full range of residential HVAC distribution repair, from spot-sealing a single disconnected flex run to complete system sealing with post-work pressure testing. Our Duct Sealing team works on the forced-air systems found in nearly every home in this city: original Carrier, Lennox, and Rheem installations from the 1960s through 1980s, often with ductwork that has never been opened since construction.
A typical sealing job in West Covina runs $450 – $1,200 for partial system work and $1,400 – $2,800 for full trunk-and-branch sealing with flex replacement. Whole-system replacement of failing galvanized duct with modern sheet metal or duct board runs higher, and we price that separately after inspection. Every quote is itemized and agreed in writing before work begins.
Pressure Testing After Sealing
We test our work. After sealing, we measure static pressure and airflow at the registers to confirm the system performs as designed. If the numbers don’t improve, we find the leak we missed and fix it. This is part of The Garrison Standard, not an upsell.
Mastic Application for Lasting Seals
We use water-based duct mastic applied with a brush or sprayer depending on access. Mastic remains flexible, handles thermal expansion, and lasts 20-plus years when applied to clean metal. In West Covina’s dry climate, it outperforms foil tape at trunk seams and plenum connections. We apply it to every joint, not just the ones we can reach easily.
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 West Covina
Our equipment roster includes Rotobrush rotary brush systems for mechanical agitation inside duct runs, Nikro negative-air machines for controlled debris extraction, and filtration products from Aprilaire, Abatement Technologies, and Guardsman. These are the same tools commercial crews use, not consumer-grade hardware. For West Covina homeowners, this means we stock parts and materials sized for residential systems common in this market. We don’t wait on shipping for standard flex duct, mastic, or register boots. If your system uses an Aprilaire media filter or a Guardsman UV assembly, we service those in place and can recommend compatible upgrades when the existing unit has reached end of life. Fast turnaround matters when the Santa Ana winds are forecast and your returns are already leaking.
Common Duct Sealing Problems We See in West Covina Homes
- Sealing only visible supply and return ducts while leaving the air handler cabinet and plenum unsealed. In 50-70 year old West Covina tract homes, that’s where most of the Colby Fire ash actually settles and leaks back into the living space. We inspect and seal the full system, including the plenum and cabinet seams.
- Using a fogging “sanitizer” upsell to mask ash odor instead of doing source removal. Fogging doesn’t remove fine soot. We use negative pressure and HEPA filtration on the return side, which is the only thing that actually removes the particulate West Covina gets after Santa Ana winds.
- Skipping camera inspection on original galvanized or early flex duct. Deteriorated interior insulation gets sealed over and keeps shedding fibers into the airstream. We look first, seal second, replace third.
- Collapsing flex duct in attic runs over 120 degrees in summer heat. West Covina attics hit extreme temperatures, and unsupported flex duct kinks and crushes. We replace with properly hung, insulated flex or rigid duct where access allows.
Pricing for Duct Sealing in West Covina, CA
Duct sealing in West Covina typically costs $450 – $1,200 for partial system work addressing specific leaks or disconnected runs. Full system sealing, including trunk line mastic application and flex duct replacement, runs $1,400 – $2,800. Homes with extensive galvanized duct deterioration requiring section replacement fall at the higher end. We do not quote per-vent pricing. We price per system, agreed in writing before work starts, and that price does not move at the door.
Several factors affect where you land in these ranges: accessibility of attic or crawl space ductwork, extent of original galvanized versus flex duct, whether the plenum and air handler cabinet also need sealing, and if we find damage requiring replacement rather than sealing. After our camera inspection, we explain each finding and price each option separately. You choose what to proceed with. Estimates are free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near West Covina
Our crews regularly work in La Puente, Covina, Baldwin Park, and Azusa. Each city has its own housing stock and climate exposures, and we adjust our approach accordingly. If you’re in one of these neighboring communities and found this page searching for West Covina service, we cover your area too. Call and we’ll confirm scheduling.
Serving West Covina, CA - Our Local Coverage Area
We’re based in the West Covina 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 About Duct Sealing in West Covina
West Covina’s position downwind of the Colby Fire burn scar means Santa Ana winds deliver fine ash and soot that coastal cities don’t receive. That alkaline ash pulls moisture and cakes onto duct interiors, accelerating corrosion and creating leak paths in aging galvanized systems. Homes in Long Beach or Torrance face salt air corrosion, but the ash-and-humidity cycle in West Covina is a distinct failure mode that sealing addresses before microbial growth takes hold. Call (361) 326-5060 for a free inspection.
Duct sealing stops the grit from recirculating by closing the leak paths where ash-laden attic or crawl space air gets pulled into the system. It does not prevent new ash from entering through your fresh air intake or open windows. For complete control, sealing should be paired with source removal cleaning using negative pressure and HEPA filtration. We offer both, priced separately, and we recommend the combination for homes south and east of the 10 and 60 freeways where ash deposition is heaviest. Call (361) 326-5060 to discuss your specific exposure.
Most 1960s West Covina homes have galvanized steel trunk lines with original seam seals that have dried and cracked, plus early flex duct runs to individual rooms with insulation that has collapsed or degraded. We regularly find pinhole leaks at trunk seams, disconnected flex at boots, and plenum gaps where the air handler connects to the distribution system. The camera shows you exactly what we see before we price any work. Call (361) 326-5060 to schedule an inspection.
No. Fogging masks odor temporarily but does not remove fine soot or ash particulate from duct surfaces. In West Covina, where Santa Ana winds deposit actual debris, source removal with mechanical agitation and negative-air extraction is the only effective method. We use Rotobrush systems and Nikro negative-air machines for this purpose. If a company pitches fogging as the solution to post-wind-event dust, they are selling you air freshener at labor rates. Call (361) 326-5060 and we’ll explain what your system actually needs.
Significant duct leaks show up as rooms that never reach temperature, dust blowing from registers even after filter changes, energy bills 20% or more above comparable homes, or visible gaps at register boots and plenum connections. We measure duct leakage during our inspection and show you the numbers. If the leakage exceeds 15% of total airflow, sealing will pay for itself in comfort and efficiency. Call (361) 326-5060 for a free estimate with no pressure to commit.
Ready to stop losing conditioned air to your attic and start breathing cleaner air in every room? Call (361) 326-5060 today for a free duct sealing estimate in West Covina. We’ll arrive inside the quoted window, inspect with a camera, price the work in writing, and stand behind it for a full year with our 365-Day Done Right Promise. Roy Castellanos and the team at Hollis Air Duct Cleaning are ready when you are.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving West Covina and the San Gabriel Valley since 2004.