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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AfterFast, Reliable Duct Sealing Across Napa
Duct sealing in Napa typically runs $800 – $2,400 for a whole-house system, and most jobs are completed in a single day with the price written down before we start. If your home was built before 1940, sits in Coombsville, or still carries smoke odor from fire season, sealing is often the fix that cleaning alone can’t deliver.
We’re the Napa crew for Hollis Air Duct Cleaning, dispatching from our San Francisco Bay Area office with technicians who know the difference between downtown Victorians with original galvanized trunks and the multi-zone systems in newer vineyard estates. We’ve worked the crawlspaces off First Street, the hillside homes near Atlas Peak Road, and the winery buildings along Silverado Trail. When you call (361) 326-5060, a live person answers – no voicemail, no callback queue – and we quote your price in writing before any tool comes out of the van.
Why Hollis Air Duct Cleaning Is Napa’s Preferred Duct Sealing Company
We’ve been in business since 2004 as part of the Garrison Partners family, and our 365-Day Done Right Promise means if our seal fails or a connected run separates, we come back and make it right at no charge – including a free second visit. That promise is backed in writing on every job, not offered verbally and forgotten.
Our technicians are background-checked, uniformed, and expected to arrive inside the quoted window, price in writing, and leave the site clean – that’s The Garrison Standard. We don’t send day laborers or subcontractors you can’t verify. The equipment we carry includes Rotobrush rotary brush systems, Nikro negative-air machines, and sealing products from Abatement Technologies and Guardsman – the same tools commercial crews use on winery HVAC systems, not hardware-store caulk guns.
Calls are answered by a live person 24 hours a day, 7 days a week. If you’re in north Napa off Trancas Street or down in the Browns Valley area, your scheduling call gets handled by someone who can actually book the appointment, not take a message.
HVAC Duct Sealing in Napa
HVAC Duct Sealing in Napa is often the missing step after Napa Dryer Vent Cleaning or duct cleaning, especially in homes where wildfire smoke or decades of duct deterioration have compromised the system. The job involves pressurizing the duct network to locate leaks, then sealing joints, boots, and trunk connections with mastic or specialized tape rated for temperature cycling – not the gray duct tape that dries and falls off in a hot attic. For a typical Napa home, whole-system sealing runs $800 – $1,800 depending on accessibility and the condition of the existing runs. Homes with original 1920s – 1940s galvanized ductwork or post-fire smoke damage in the Coombsville and Atlas Peak areas often land in the $1,400 – $2,400 range because we’re isolating and replacing failed sections, not just coating seams.
Smoke-Taint Sealing for Fire-Affected Systems
After the 2020 Glass Fire, we saw a pattern in east Napa homes: cleaning removed visible ash, but odor returned within days because leaks in the return side were pulling contaminated air from wall cavities and crawlspaces back into the living space. Sealing those pathways breaks the re-entrainment loop. We run a camera first, then seal under negative pressure with an Abatement Technologies HEPA unit attached so nothing migrates room to room during the work.
Mastic Sealing vs. Tape-Only Methods
Mastic is a water-based sealant we brush onto joints and seams that remains flexible as the duct expands and contracts with heating and cooling cycles. Tape alone cracks. In Napa’s climate – hot, dry summers and damp winters – that flexibility matters. We use mastic on galvanized trunk lines and tape-reinforced mastic on flex duct connections where movement is greatest.
Duct Repair in Napa
Duct Repair in Napa frequently means something more involved than sealing a leak. In the pre-1940 bungalows and Victorians downtown, we find crushed flex runs, rusted-through galvanized trunks, and splices made by previous owners that disconnected years ago and have been blowing conditioned air into crawlspaces ever since. Repair costs in Napa range from $400 – $900 for isolated flex replacement or boot reconnection to $1,200 – $2,800 when we’re replacing a section of galvanized trunk or rebuilding a plenum. The price is written before we cut anything.
Disconnected and Crushed Runs
A common find in older Napa homes: a flex duct run that was stepped on during a re-roofing job or detached when a rodent got into the crawlspace. The register still blows air, but it’s half the volume it should be, and the other half is heating your crawlspace. We reconnect with proper supports and seal the joint so it stays put. Our Duct Sealing team carries the full range of flex diameters and transition fittings so we’re not making a second trip.
Galvanized Trunk Replacement
Original galvanized steel trunk lines in downtown Napa develop pinhole corrosion and seam separation that no sealant can reliably fix. When we find this, we isolate the failed section, fabricate a replacement in galvanized or switch to insulated flex where appropriate, and seal all new connections. We also check whether the original sizing still matches the load – many 1930s systems were never designed for modern HVAC blower pressures.
Trusted Brands We Service in Napa
We stock parts and sealing materials from Abatement Technologies, Guardsman, and Aprilaire so most Napa repairs don’t wait on shipping. Abatement Technologies HEPA filtration units let us work under negative pressure in occupied homes and winery tasting rooms without cross-contaminating spaces. Guardsman sealants and mastics are rated for the temperature swings we see in unconditioned Napa attics and crawlspaces. Aprilaire whole-home dehumidifiers and air cleaners integrate with sealed duct systems for homeowners who want to address both the leak and the indoor air quality downstream. Because we carry this inventory locally, a technician arriving in Browns Valley or up near Skyline Park has what’s needed on the van rather than ordering parts and rescheduling.
Common Duct Sealing Problems We See in Napa Homes
- Pinhole corrosion in original galvanized trunks. Downtown Napa’s pre-1940 homes often have ductwork that predates modern sealing standards. The seams were folded and screwed, not sealed, and eighty years of condensation have rusted pinholes through the metal. Sealing the visible boot does nothing when the trunk itself is leaking into the wall cavity.
- Smoke residue re-entrained through return leaks. After major fires like the 2020 Glass Fire, homeowners in Coombsville and Atlas Peak cleaned their ducts but still smelled smoke. The odor source was in the return plenum or wall chase, and every blower cycle pulled it back through leaks upstream of the filter. Sealing the return side breaks that loop.
- Winter condensation on cold duct runs. Napa’s winter dampness condenses on uninsulated galvanized ducts in vented crawlspaces. A sealant bead applied over that moisture fails within a season because it can’t adhere to wet metal. We dry the surface, insulate where needed, then seal.
- Failed flex splices in 1960s – 70s tract homes. North Napa subdivisions like those off Trancas Street used early flex duct that degrades and separates at the collar. The splice was often taped with a product that turned to powder after thirty summers in the attic. We replace the damaged section and seal with mastic and a mechanical clamp.
Pricing for Duct Sealing in Napa, CA
Whole-house duct sealing in Napa typically costs $800 – $1,800 for accessible systems in good structural condition. Homes with original pre-1940 galvanized ductwork, post-wildfire smoke remediation needs, or multiple disconnected runs – common in Coombsville, Atlas Peak, and downtown neighborhoods – generally fall between $1,400 – $2,400. Duct repair as a standalone service runs $400 – $900 for isolated fixes and $1,200 – $2,800 for trunk replacement or plenum rebuilds.
What moves the price: accessibility (crawlspace height, attic hatch location), the linear footage of ductwork, whether we can seal in place or must replace failed sections, and whether smoke remediation requires negative-pressure containment. We do not quote per-vent or per-square-foot teaser prices that balloon once we’re inside. The price is written down before work starts, and it does not move at the door. Estimates are free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Napa
Our crews work throughout the Napa Valley and surrounding areas, including Duct Sealing in Napa proper as well as Boyes Hot Springs, Sonoma, Winters, and Fairfield. Scheduling and dispatch are coordinated from our San Francisco Bay Area office, with local technicians serving each community.
Serving Napa, CA - Our Local Coverage Area
We’re based in the Napa 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 Napa
Cleaning removes debris; sealing fixes the pathways that let smoke, attic air, and crawlspace moisture back into the system. In downtown Napa’s pre-1940 homes, the original ductwork was never designed to be airtight – folded seams, unsealed boots, and retrofitted flex splices leak conditioned air into walls and under the house. We’ve cleaned systems that tested dirty again within months because the leaks were never addressed. Sealing after cleaning is what keeps the air you paid to condition actually reaching the rooms. Call (361) 326-5060 and we’ll inspect both the cleanliness and the integrity of your runs.
Yes, sealing is often the specific fix for persistent smoke odor. After the 2020 Glass Fire, we found that cleaning removed ash from accessible duct surfaces but odor returned because return-side leaks were pulling contaminated air from wall cavities and crawlspaces back through the system. A Coombsville homeowner on the east side of Napa called us after exactly this problem; our tech put a camera inspection through the supply and return ducts and found two detached flex runs in the crawlspace and a rusted-through galvanized trunk feeding the original 1930s floor registers. We isolated the failed sections, reconnected the runs with new flex, and sealed the trunk and boot joints with mastic while the Rotobrush and Abatement Technologies HEPA unit held the system under negative pressure – the odor readings dropped and the homeowner finally stopped running the HVAC fan on “on” to mask it. If your Coombsville or Atlas Peak home still smells like smoke after cleaning, the ducts likely need sealing or repair, not another cleaning. Call (361) 326-5060 for a camera inspection.
We pressurize the duct network with a fan and measure leakage, then use a camera to locate the worst points. On older Napa systems, we often find we need to abandon crushed or rusted sections rather than seal them – a pinholed galvanized trunk can’t be reliably sealed, and a disconnected flex run needs reconnection first. We seal accessible joints with mastic, replace failed sections with new flex or fabricated galvanized, and test again to verify the leakage rate dropped. The work typically takes four to six hours for a downtown Victorian or bungalow. Call (361) 326-5060 for an exact scope and price.
Yes. Modern vineyard estates and winery buildings in Napa often use multi-zone HVAC with dampers and variable-speed blowers that require more precise balancing than single-zone systems. We seal each zone independently, verify damper operation, and test that zone pressures remain balanced after sealing. For winery tasting rooms, we work under negative pressure with HEPA containment so sealing activities don’t introduce dust or odors into barrel storage or guest areas. The same written price and 365-Day Done Right Promise apply. Call (361) 326-5060 to discuss your system’s configuration.
Signs of crushed or disconnected runs include rooms that never reach temperature, registers with weak airflow despite a loud blower, or dust streaks around ceiling boots where attic air is being pulled through gaps. We confirm with a camera inspection – a flexible scope sent through the duct shows collapsed flex, detached collars, or rusted-through metal that sealing alone won’t fix. In Napa’s older homes, especially those with crawlspace ductwork off First Street or in the Browns Valley area, we find disconnected runs on about one in three inspections. The camera footage is shared with you before we quote repair versus sealing. Call (361) 326-5060 to schedule an inspection – estimates are free.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Napa and the Bay Area since 2004.