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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Before
AfterFast, Reliable Duct Sealing Across San Bruno
Duct sealing in San Bruno typically runs $1,200 – $2,800 for a whole-home system, depending on whether we’re working with original post-WWII galvanized ductwork or the builder-grade flex runs installed in Crestmoor and Mills Estates rebuilds. Our Duct Sealing team serves San Bruno from our Bay Area dispatch office, and we schedule most jobs within a week because we keep mastic, mechanical fasteners, and camera inspection gear stocked for the specific duct types common here. Call (361) 326-5060 for a written estimate before any work starts.
San Bruno sits in that narrow coastal band where the marine layer parks itself for weeks at a time. That persistent fog isn’t just a weather pattern; it’s the reason your ducts behave differently than they would in San Jose or Walnut Creek. We’ve sealed ductwork from the original 1950s tracts near El Camino Real to the rebuilt homes in Crestmoor, and the problems we find are rarely the same as what inland crews see. The moisture profile here is unique. The salt-laden air doesn’t dry out between HVAC cycles. And the duct systems installed after the 2010 pipeline explosion are now old enough to show their first real wear.
Why Hollis Air Duct Cleaning Is San Bruno’s Preferred Duct Sealing Company
We’ve been part of the Garrison Partners family since 2004, and our San Bruno work comes through referrals from neighbors who’ve already had us in their homes. Roy Castellanos built this operation on The Garrison Standard: written prices, written guarantees, and technicians who arrive inside the quoted window in uniform with background checks already completed. No voicemail loops, no callback queues. A live person answers the phone 24 hours a day.
Our 365-Day Done Right Promise applies to every duct sealing job in San Bruno. If a sealed joint fails, if a boot pulls loose, if the musty odor returns because we missed a seam, we come back and make it right at no charge. That includes a free second visit. We put it in writing on every invoice.
Dispatch and scheduling for San Bruno run through our Bay Area office, but the crews that arrive at your door are local. They know the difference between a 1952 tract home on Crystal Springs Road and a 2012 rebuild on Skyline Boulevard. They carry the right fasteners for galvanized steel and the right mastic for flex duct. That local knowledge saves time and prevents callbacks.
Duct Sealing Services in San Bruno
Duct Sealing Services in San Bruno address a specific coastal problem: damp, salt-laden air leaking into your duct runs through gaps at joints, boots, and the air handler cabinet, then condensing on cooler surfaces and feeding microbial growth. A typical whole-home duct sealing job in San Bruno runs $1,200 – $2,800, with simpler single-zone repairs starting around $450. We price by the system, not by the linear foot, and we write the number down before touching anything.
Supply Duct Sealing
Supply ducts carry conditioned air to your rooms, but in San Bruno’s post-WWII tracts, we’ve found original galvanized runs with gaps at every joint where the original sealant has hardened and cracked. In Crestmoor and Mills Estates rebuilds, builder-grade flex duct sags at low points where the marine layer’s moisture pools. We seal supply joints with mastic, reinforce with mechanical fasteners where the duct material allows, and verify with camera inspection. No guesswork.
Return Duct and Air Handler Sealing
The return side pulls air back to your HVAC unit, and in San Bruno, unsealed return boots often draw damp garage or crawlspace air straight into the system. We seal the air handler cabinet seams, the return plenum, and every boot connection. This is the work most crews skip because it’s awkward overhead work in tight spaces. We don’t skip it. The return side is where your indoor air quality actually gets made.
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.
Duct Insulation in San Bruno
Duct Insulation in San Bruno solves a problem that inland Bay Area homeowners rarely face: condensation on the exterior of cool supply ducts running through warm, humid attic or crawlspace air. When your AC runs, the duct surface temperature drops below the dew point of San Bruno’s fog-laden air, and water beads on the metal or flex wrap. A typical duct insulation job in San Bruno runs $800 – $1,900 for a whole-home system, depending on accessibility and whether we’re wrapping existing sealed ducts or insulating as part of a full sealing and cleaning package.
Vapor-Barrier Wrapping
We use insulation with an intact vapor barrier, sealed at every seam with appropriate tape and mastic. In San Bruno’s climate, a torn or poorly sealed vapor barrier is worse than no insulation at all; it traps moisture against the duct surface and accelerates corrosion on galvanized steel or breakdown of flex duct outer layers. We inspect the barrier integrity before we leave.
Condensation Control for Coastal Conditions
Our crews calculate the dew point differential for your specific duct runs and recommend insulation R-values that actually prevent condensation in San Bruno’s marine climate, not just meet minimum code. The goal is dry duct surfaces year-round, even when the fog sits on the peninsula for a week straight.
Trusted Brands We Service in San Bruno
We stock sealing and filtration components from Honeywell, Aprilaire, and Abatement Technologies for San Bruno jobs, which means we don’t wait on shipping when your system needs a specific boot gasket or plenum seal. Our negative-air equipment comes from Nikro, and we carry rotary brush systems for the agitation work that precedes sealing on microbially active ducts. For homeowners in the Mills Estates and Crestmoor areas, this parts availability matters because builder-grade components from the 2010 – 2015 rebuild period are starting to fail on predictable schedules, and we’ve already sourced the replacement profiles.
Common Duct Sealing Problems We See in San Bruno Homes
- Sealing over wet, microbially active flex duct without source removal. We see this on Crestmoor rebuilds where a previous crew fogged the ducts and sealed them, trapping live mold inside the run. The musty smell always returns within weeks. We remove the contaminated material first, then seal the replacement or cleaned duct.
- Foil tape applied to sagging flex duct low points. Tape alone can’t support the duct, and San Bruno’s temperature swings between foggy mornings and afternoon sun cause expansion-contraction cycles that foil tape fails within one season. We use mechanical support plus mastic on flex runs.
- Skipping return-side and air handler cabinet seams. These are the hardest areas to reach in crawlspaces and attics, but they’re also where San Bruno homes pull the dampest unconditioned air into the system. We seal every accessible seam, and we document what we can’t reach.
- Galvanized steel corrosion at original joints in pre-1970 tracts. The salt in San Bruno’s marine air accelerates rust at duct seams where the original sealant has failed. We clean the joint, treat light corrosion, and seal with mastic rated for metal duct applications.
Pricing for Duct Sealing in San Bruno, CA
Whole-home duct sealing in San Bruno typically costs $1,200 – $2,800. Single-zone or partial-system repairs start around $450. Duct insulation runs $800 – $1,900 for a full system. What moves you within these ranges: the duct material (galvanized steel takes more labor than flex), accessibility (crawlspace work costs more than basement or garage access), and whether we need to remove contaminated duct material before sealing.
We don’t quote per-vent prices. That structure invites bait-and-switch tactics we’ve all heard about. We price by the system, write it down before work starts, and it doesn’t move at the door. Every estimate is free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near San Bruno
Our crews work throughout the northern Peninsula. We regularly seal ducts in San Bruno and the surrounding communities of Millbrae, South San Francisco, Pacifica, and Brisbane. The same marine-layer conditions affect duct systems across this corridor, and we bring the same equipment and the same written pricing to every job.
Serving San Bruno, CA - Our Local Coverage Area
We’re based in the San Bruno 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 San Bruno
San Bruno’s marine layer keeps duct surfaces damp year-round, so mold and mildew establish in low points and joint gaps without waiting for a wet season. Inland ducts dry out between cycles; San Bruno ducts rarely do. Call (361) 326-5060 if you’re noticing musty air when the system first kicks on.
Yes. Builder-grade flex duct installed during 2010 – 2015 reconstruction is now 10 – 15 years old, and we’re finding sagging runs with debris accumulation and microbial growth at low points. The duct material hasn’t failed, but the sealing integrity and internal cleanliness need attention. We inspect with cameras and give you a written condition report before quoting any work.
No. Fogging does not remove the source of microbial growth; it deposits chemical residue on duct surfaces while leaving the actual contamination in place. In San Bruno’s damp climate, that moisture and organic material stays active. We recommend mechanical source removal with agitation tools under negative pressure, followed by sealing to prevent reinfiltration. That’s the combination that actually solves the problem.
Sealing prevents unconditioned, moisture-laden air from entering the duct system through gaps and seams. When your ducts are tight, the air moving through them is the air you’ve already conditioned, with controlled humidity. Sealing doesn’t remove existing moisture, but it stops the continuous reintroduction of fog-laden air that feeds microbial growth. We typically pair sealing with source removal on actively contaminated systems.
Yes. We seal original galvanized steel with mastic rated for metal applications, and we address the corrosion that San Bruno’s salt air accelerates at original joints. Some tracts near El Camino Real and Crystal Springs Road have ductwork from the 1940s and 1950s that’s still structurally sound but badly leaking. We assess whether sealing extends useful life or whether section replacement makes more sense, and we give you both options in writing.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving San Bruno and the Bay Area since 2004.