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 Kentfield
If you’re noticing uneven heating between rooms, rising PG&E bills, or a persistent musty smell when your furnace kicks on, leaky ducts are likely the culprit. In Kentfield, where most homes were built without air conditioning and heating systems may not have been touched in decades, duct sealing often delivers the single biggest efficiency improvement a homeowner can make. Our crews dispatch from the San Francisco Bay Area office and serve Kentfield properties directly, carrying the rotary brush systems and negative-air equipment needed to seal systems properly the first time. Call (361) 326-5060 for a free written estimate.
Why Hollis Air Duct Cleaning Is Kentfield’s Preferred Duct Sealing Company
Kentfield homeowners know the difference between a crew that understands hillside construction and one that’s guessing. We’ve worked on enough mid-century ranches along Woodland Road and in the Kent Woodlands to recognize the original galvanized ductwork that builders installed in the 1960s, and we know how the damp coastal air accelerates corrosion at the seams.
Our reputation here is built on showing up inside the quoted window, pricing the job in writing before any work starts, and leaving the site clean. That’s The Garrison Standard, and it’s how every Hollis technician is expected to operate on every Kentfield job.
Roy Castellanos leads our operation with a straightforward approach: background-checked, uniformed technicians who explain what they’re finding as they find it, and a 365-Day Done Right Promise that covers every repair in writing. If the seal fails within a year, we return and make it right at no charge, including a free second visit.
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 for someone to pick up.
Duct Repair in Kentfield
Duct Repair in Kentfield typically addresses the deteriorated galvanized or early flexible ductwork found in homes built between the 1950s and 1970s, where seams have separated, hangers have failed, or sections have collapsed in crawl spaces. Because most Kentfield properties were never fitted for air conditioning, these heating-only systems often went unmaintained for twenty or thirty years, and the damage becomes visible only when rooms stop heating evenly or utility bills spike unexpectedly. A typical duct repair in Kentfield runs $280 – $520 for sectional replacement or reconnection, with full system rehabilitation ranging $800 – $1,400 depending on accessibility and the extent of corrosion.
Collapsed Sections in Crawl Spaces
In the canyon lots off Sir Francis Drake Boulevard, we’ve found duct runs that have literally fallen off their supports and are resting on damp soil, drawing in crawl space air rather than delivering conditioned air to the rooms above. We lift, re-support, and seal these sections with mastic and mechanical fasteners that hold up to the humidity.
Corroded Galvanized Trunk Lines
The original metal trunk lines in Kentfield’s mid-century ranches develop pinhole leaks at the seams where decades of fog-season moisture have done their work. Our crew cuts out the damaged span and replaces it with properly sized flex duct or sheet metal, sealed at every joint.
Air Duct Sealing in Kentfield
Air Duct Sealing in Kentfield focuses on closing the gaps, cracks, and disconnected joints that allow heated air to escape into attics and crawl spaces before it ever reaches your living areas. For a typical 1,800-square-foot ranch in the Kentfield Hills, we regularly measure duct leakage at 25 – 35% of total airflow, which means roughly a third of your heating bill is warming spaces you don’t occupy. A complete air duct sealing in Kentfield typically costs $650 – $1,100 for a single system, with larger custom hillside homes running $1,200 – $1,800 depending on the complexity of the duct layout and the number of attic access points.
Mastic Sealing at Every Joint
We apply duct sealing mastic, a thick, fiber-reinforced compound, to every accessible joint and seam. Unlike tape, which dries and fails within a few years in damp crawl spaces, mastic remains flexible and maintains its seal through Kentfield’s wet winters and foggy summers.
Pressure Testing After Completion
Our crew runs a post-seal pressure test using a calibrated fan to verify that leakage has dropped to acceptable levels. We show you the before and after numbers in writing, so you know exactly what was accomplished.
Trusted Brands We Service in Kentfield
Our vans carry professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies, plus filtration and sealing products from Honeywell, Aprilaire, and Guardsman. For Kentfield homeowners, this means we rarely need to order parts and wait, even for older systems. The rotary brush systems handle the fine redwood and oak pollen that collects in Kentfield ducts, while our negative-air machines maintain proper containment during any remediation work. When we recommend a filtration upgrade after sealing, we’re specifying products we’ve installed on local homes and can show you how they perform in real Kentfield conditions.
Common Duct Sealing Problems We See in Kentfield Homes
- Original ductwork never designed for efficiency. Most Kentfield homes were built when energy was cheap and duct leakage was not a consideration. The uninsulated flex runs and unsealed metal connections from the 1960s and 70s bleed heated air into attics that stay damp through the fog season.
- Redwood and oak debris clogging returns. After a windy October, our technicians regularly find redwood needles and fine oak pollen packed into return registers under eaves on canyon lots, restricting airflow and forcing the system to overwork.
- Surface mold in unsealed crawl spaces. Kentfield’s mild, damp winters promote microbial growth on duct exteriors where warm air meets cool, moist crawl space air. Sealing the duct interior prevents spore circulation; cleaning the exterior often requires coordinated remediation.
- Hillside settling shifting duct runs. Custom homes on Kentfield’s steeper lots experience gradual foundation movement that pulls duct connections apart at the plenum and register boots, creating leaks that compound over years.
Pricing for Duct Sealing in Kentfield, CA
Honest pricing starts with honest ranges. In Kentfield’s market, spot sealing of accessible leaks runs $280 – $450, while comprehensive whole-system sealing with pressure testing typically falls between $650 and $1,100 for a standard single-system home. Larger custom properties with multiple zones or difficult attic access range $1,200 – $1,800. What moves the needle: the age and condition of existing ductwork, whether we need to remove degraded insulation, the number of hard-to-reach runs, and whether mold remediation is required before sealing can begin.
We give you one flat price per system, agreed in writing before any work starts. No per-vent pricing, no add-ons once the van is in your driveway. Every estimate is free, and we bring before-and-after photos from previous Kentfield jobs so you can see what proper sealing looks like. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Kentfield
Our crews work throughout southern Marin County, including Duct Sealing in Kentfield and neighboring Larkspur, San Anselmo, San Rafael, and Corte Madera. If you’re outside Kentfield proper but within the broader service radius, the same written pricing, same equipment, and same 365-Day Done Right Promise apply. We also handle Air Duct Cleaning in Kentfield and Dryer Vent Cleaning in Kentfield for homeowners who want their full system addressed in one visit.
Serving Kentfield, CA - Our Local Coverage Area
We’re based in the Kentfield 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 Kentfield
We typically schedule Kentfield appointments within 3 – 5 business days, with written confirmation of your arrival window. Dispatch is coordinated from our San Francisco Bay Area office, and crews carry the equipment to complete most single-system sealings in one visit. Call (361) 326-5060 for the next available slot.
Yes. We work throughout Kentfield, including the Kent Woodlands, the flatlands near College Avenue, and the hillside properties along Woodland Road and Sir Francis Drake Boulevard. Each area presents different duct access challenges, and our technicians arrive prepared for the construction type they’ll encounter.
We do not advertise emergency dispatch for duct sealing, as it is a scheduled improvement rather than an urgent repair. However, our phones are answered by a live person 24/7, and if a leaking duct has created an immediate air quality or heating failure, we’ll prioritize your appointment and advise on interim steps.
Kentfield pricing sits in line with southern Marin County generally, slightly above inland markets like San Rafael flatlands due to hillside access complexity and the prevalence of custom homes with longer duct runs. The $650 – $1,100 range for standard homes reflects local labor rates and the specialized equipment needed for damp-climate sealing.
Every duct sealing job is backed by our 365-Day Done Right Promise in writing. If any sealed joint fails, any mastic cracks, or leakage returns to pre-seal levels within one year, Hollis returns and makes it right at no charge, including a free second visit. The guarantee is not prorated, not limited, and not subject to negotiation at the door.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Kentfield and the San Francisco Bay Area since 2004.