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 San Rafael
San Rafael homeowners call us when their HVAC system runs constantly but rooms stay cold, or when dust reappears hours after cleaning. Duct sealing in San Rafael typically costs $850 – $2,400 for a whole-home seal, depending on whether we’re working with original redwood-framed returns in a West End Victorian or long flex runs in a Terra Linda Eichler. We dispatch crews from our San Francisco Bay Area office and serve San Rafael neighborhoods directly. Call (361) 326-5060 for a free estimate with a written price before any work starts.
Why Hollis Air Duct Cleaning Is San Rafael’s Preferred Duct Sealing Company
We’ve been in business since 2004 as part of the Garrison Partners family, and our Duct Sealing team knows San Rafael’s housing stock inside and out. The split between pre-1950s downtown and West End Victorians and 1960s-70s Terra Linda tract homes means no two jobs are identical. Our technicians are background-checked, uniformed, and expected to behave by The Garrison Code: arrive inside the quoted window, price in writing, complete the job by the book, and leave the site clean.
Every repair we perform in San Rafael carries our 365-Day Done Right Promise in writing. If the work fails within a year, we return and make it right at no charge, including a free second visit. The price is written down before any work starts, and it does not move at the door. Phones are answered by a live person 24 hours a day, 7 days a week, so you’re not waiting until Monday to schedule.
Duct Insulation in San Rafael
Duct Insulation in San Rafael addresses a specific problem: the original fiberglass or rodent-chewed wrapping around ducts in crawlspaces and attics that has compressed, torn, or absorbed moisture over decades. In Marin County’s mild, wet winters and dry summers, HVAC systems run less than inland, so duct insulation degrades slowly and often gets ignored until homeowners notice hot rooms in summer or cold spots in winter. A typical Duct Insulation job in San Rafael runs $600 – $1,800, depending on linear footage and whether we’re re-wrapping accessible flex duct or insulating original redwood chases that were never lined.
When Insulation Fails in Older Homes
West End and downtown Victorians frequently have uninsulated or poorly insulated panned joist returns and redwood-framed plenums. We remove degraded material, seal air leaks first, then install new insulation rated for the location, attic or crawlspace. Without sealing first, new insulation just hides the leaks.
Eichler and Ranch Tract Solutions
Terra Linda and Mont Marin homes with long flex runs often have insulation that has slid down the duct, leaving bare sections near the plenum. We re-secure or replace the insulation and verify R-value matches what Marin County’s climate demands, not what worked in Sacramento or Fresno.
HVAC Duct Sealing in San Rafael
HVAC Duct Sealing in San Rafael closes the gaps, cracks, and disconnected joints that let conditioned air escape into attics, crawlspaces, and wall cavities. In a typical San Rafael home, we find 20 – 35% air loss through the duct system before it ever reaches the vents. HVAC Duct Sealing runs $850 – $2,400 in San Rafael, with simpler Terra Linda ranch jobs at the lower end and complex West End Victorians with multiple disconnected galvanized runs at the upper end.
Hand-Sealing Original Materials
Pre-1950s homes with redwood-framed plenums and galvanized branch runs need mastic and mesh applied by hand, not aerosol sealant or foil tape. The joints are irregular, corroded, and often inaccessible behind original framing. Our crews carry the tools to work in tight crawlspaces and seal what tape cannot grip.
Reconnecting Crushed and Disconnected Runs
Camera inspections in San Rafael regularly find flexible duct crushed behind redwood framing or completely separated at couplings. We reconnect, support, and seal these runs so static pressure returns to design spec and the blower motor stops short-cycling.
Trusted Brands We Service in San Rafael
We seal and service duct systems connected to equipment from Honeywell, Aprilaire, and Abatement Technologies, and we stock common fittings and sealants for San Rafael customers so turnaround stays short. Our crews use Nikro negative-air machines during pre-seal cleaning to remove debris before we close the system, and we specify Honeywell and Aprilaire filtration upgrades when a sealed duct system needs better protection against the pollen and dust that blow in from Marin County open space. We don’t sell hardware-store tape or temporary fixes. The materials we use are the same ones commercial crews specify for hospitals and schools, sized right for your home.
Common Duct Sealing Problems We See in San Rafael Homes
- Corroded galvanized joints in West End Victorians. Original branch runs from the 1920s – 1940s rust at the seams, especially in crawlspaces with seasonal moisture. Tape won’t bond to corrosion; we wire-brush, apply mastic and mesh, and sometimes replace short sections.
- Crushed flex duct behind redwood framing. Eichler-style and mid-century homes in Terra Linda have long flex runs that sag or get compressed during other trades’ work. We restore proper diameter and support every six feet to prevent recurrence.
- Rodent-chewed entries near open space. Homes near Dominican University and the open-space corridors have original foundation and attic vents that never got screens. We seal duct damage, but we also flag the entry points so an exclusion specialist can close them before our work gets destroyed.
- Unsealed returns pulling attic air. Original panned joist or redwood chase returns in downtown Victorians are open to wall and attic cavities. Sealing only the supply side leaves the problem intact; we seal both sides of the system.
Pricing for Duct Sealing in San Rafael, CA
A typical whole-home duct sealing in San Rafael runs $850 – $2,400. Smaller Terra Linda ranch homes with accessible flex duct and a single plenum usually fall at the lower end. West End Victorians with multiple disconnected galvanized runs, hand-sealing around original redwood framing, and crawlspace access issues run higher. What moves the price: linear footage of duct, accessibility (crawlspace height, attic pitch), whether we need to replace crushed or rodent-damaged sections, and whether the return side needs sealing too. We give one flat price per system, agreed in writing before work starts. No per-vent pricing, no add-ons at the door. Call (361) 326-5060 for a free estimate. We’ll inspect the system, show you what we find, and write the price down.
We Also Serve Cities Near San Rafael
Our crews work throughout central Marin County. We regularly seal ducts in San Rafael and nearby Larkspur, Kentfield, Corte Madera, and San Anselmo. The same written pricing, same 365-Day Done Right Promise, same background-checked uniformed technicians apply in every town we serve.
Serving San Rafael, CA - Our Local Coverage Area
We’re based in the San Rafael 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 Rafael
Yes, in most cases. We hand-seal corroded joints with mastic and mesh, which bonds to irregular surfaces better than tape or aerosol sealant. Replacement is only necessary when galvanized branch runs have rusted through or redwood framing itself has rotted. Call (361) 326-5060 and we’ll camera-inspect to tell you which category you’re in.
Roof rats and deer mice from the corridors near Dominican University and the surrounding hills enter through original unscreened foundation and attic vents, then chew flex duct and nest in insulation. Marin County’s mild winters mean rodents stay active year-round. We seal duct damage and flag the entry points for exclusion work.
Eichlers and similar mid-century homes have long, straight flex runs that are easy to access but prone to crushing and sagging; sealing focuses on reconnection, support, and sealing couplings. Downtown Victorians have short, rigid galvanized branches in irregular redwood chases that demand hand-sealing in tight spaces. The tools and time differ significantly.
Yes, because dust accumulation in San Rafael comes from pollen, open-space debris, and rodent activity pulled through leaks, not just heavy system use. Sealing the return side stops attic and crawlspace air from entering the system. Less debris enters, so less circulates, even at lower runtime hours.
Yes. We follow NADCA guidelines for inspection, cleaning before sealing, and verification of seal integrity. Our negative-air source removal with Nikro equipment precedes sealing work, and we verify results with static pressure and visual checks. The 365-Day Done Right Promise covers our sealing work in writing.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving San Rafael since 2004.