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 Fremont
Duct sealing in Fremont typically costs $450 – $1,200 for a whole-house seal, depending on access and how many runs need mastic or metal repair. Most jobs take a half day, and we price them in writing before any work starts. If your registers barely blow air or your utility bills spike every summer, the problem is usually leaky joints, not dirty ducts.
We’re the crew Hollis Air Duct Cleaning sends to Fremont from our San Francisco Bay Area dispatch office. Our technicians know the difference between a 1958 Centerville tract home with original galvanized steel and a 2021 Warm Springs townhome with flex duct packed in a shared wall. That matters because the fix is completely different. Call us at (361) 326-5060 for a free estimate, or read on to see what we actually find in Fremont houses.
Why Hollis Air Duct Cleaning Is Fremont’s Preferred Duct Sealing Company
Hollis has been part of the Garrison Partners family since 2004. We don’t chase the lowest teaser price. We compete on discipline: show up inside the window, price it before we touch it, do it by the book. That standard, The Garrison Standard, is written down and enforced on every job.
Fremont homeowners call us back because our price doesn’t move at the door. Ever. We write it down. You sign it. Then we work. Our 365-Day Done Right Promise covers every seal and repair for a full year. If a joint we sealed fails, we return and make it right at no charge, including the second visit.
Our technicians are background-checked and uniformed. You know who’s walking in before they arrive. Our phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops. No callback queues.
We carry professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies. The same tools commercial crews use. We explain what we’re doing in plain terms, not jargon, because you should understand what you’re paying for.
Duct Repair in Fremont
Duct Repair in Fremont is usually about fixing what decades of settling, remodeling, and retrofitted central air have broken. In the older tracts around Irvington and Centerville, including the historic Niles district, technicians commonly find ductwork that was retrofitted for central air decades after the homes were built. Often with undersized returns and leaky joints hidden behind original plaster walls. Cleaning that system just blows dust through the same leaks. The real fix is sealing and airflow balancing.
We also see galvanized trunk lines crushed or disconnected during mid-century remodels, letting conditioned air dump into crawlspaces rather than registers. A typical duct repair in Fremont runs $280 – $650 for accessible trunk work, or $450 – $1,200 if we need to open walls or access a buried junction.
Crushed or Disconnected Trunk Lines
Original galvanized steel doesn’t flex. When a Fremont homeowner adds a hallway, a bathroom, or a slab extension, the trunk line often gets compressed or severed. We locate the break with a camera, then rebuild or reroute with sheet metal and mastic. The goal is getting air back to the registers, not just cleaning around the damage.
Undersized Returns Behind Plaster
Retrofit crews in the 1970s and 1980s sometimes squeezed return ducts into wall cavities never designed for airflow. The result is a system that runs constantly, overheats the blower, and never reaches set temperature. We enlarge or reroute returns where possible, then seal every joint so the air moves through the house, not the walls.
Air Duct Sealing in Fremont
Air Duct Sealing in Fremont addresses the gaps, cracks, and failed joints that let conditioned air escape before it reaches your rooms. In Fremont’s mid-century tracts like Irvington and Centerville, duct systems were often retrofitted with central air decades after construction, leaving undersized returns and leaky joints buried behind original plaster walls. Sealing and balancing matters more than cleaning in these homes. The city’s alluvial Bay Mud and creek-bed silt soils also mean seasonal dust and pollen pull into these same runs differently than in neighboring cities on firmer ground.
A typical whole-house air duct sealing in Fremont runs $450 – $1,200. Partial sealing of accessible basement or attic runs starts around $280. We use mastic, metal tape, and mechanical fasteners, not duct tape, because duct tape fails in heat and vibration.
Mastic Sealing for Leaky Joints
Mastic is a thick, brush-on sealant that fills gaps in metal and flex duct. We apply it to every joint, collar, and penetration after cleaning. It cures flexible and lasts decades. In Fremont’s older homes, we often find original joints that were never sealed at all, just friction-fit together. Those leak 20 – 30 percent of airflow.
Pressure Testing After the Seal
We test our work. After sealing, we run a pressure differential check to confirm the system holds. If it doesn’t, we find the leak and fix it before we leave. That’s part of The Garrison Code. No guesswork. No “it should be better.”
Trusted Brands We Service in Fremont
We stock parts and filtration products from Honeywell, Aprilaire, and Guardsman, with professional-grade sealing and cleaning equipment from Rotobrush, Nikro, and Abatement Technologies. For Fremont customers, that means we don’t order parts and make you wait. We carry the collars, mastic, metal tape, and replacement registers that match your system. Most repairs and full seals are completed same visit. If we hit something unusual, like a custom plenum from a 1960s Carrier system in a Niles cottage, we source it fast through our Bay Area supplier network. Fast turnaround matters because a house without sealed ducts in July is a house that never cools down.
Common Duct Sealing Problems We See in Fremont Homes
- Retrofitted central-air systems behind original plaster walls in Irvington and Centerville. Undersized returns and hidden joint leaks that cleaning alone never corrects. We seal what we can access and recommend wall openings only when the airflow gain justifies the repair cost.
- Galvanized trunk lines crushed or disconnected during mid-century remodels. Conditioned air dumps into crawlspaces rather than registers. Homeowners wonder why the back bedrooms never cool. We find the break, rebuild the trunk, and seal the new joints.
- New Warm Springs and Bayside townhomes with short, elbow-heavy duct runs. Shared-wall penetrations collect drywall dust and construction debris that leaks past poorly sealed collars. The fix is collar replacement and mastic sealing, not just vacuuming.
- Seasonal pollen and dust drawn through leaky return plenums. Fremont’s dry summers make this dust airborne; winter bay moisture can trigger mold in the same leaks. Sealing the return side stops both problems at the source.
Pricing for Duct Sealing in Fremont, CA
Whole-house duct sealing in Fremont typically runs $450 – $1,200. Partial sealing of accessible runs in an attic or crawlspace starts at $280 – $450. Duct repair for crushed or disconnected trunk lines ranges $280 – $650 for accessible work, or $450 – $1,200 if we need to open walls or access buried junctions behind original plaster.
What moves the price: how many runs need sealing, whether we need to access buried ductwork, and if any sections require replacement rather than sealant. We inspect first, price in writing, and you approve before we start. No per-vent pricing. No add-ons at the door. One flat price per system.
Every estimate is free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Fremont
Our crews work throughout the East Bay. We regularly seal ducts in Fremont as well as Newark, Union City, Hayward, and Pleasanton. Each city has different housing stock and different duct problems. We adjust our approach accordingly. If you’re in one of these neighboring cities and found this page, call us. We know your area too.
Serving Fremont, CA - Our Local Coverage Area
We’re based in the Fremont 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 Fremont
Because the ductwork was retrofitted decades after the house was built, often with undersized returns and leaky joints hidden behind original plaster walls. Cleaning blows dust through those same leaks. Sealing stops the air loss and balances the system so every room gets airflow. Call (361) 326-5060 and we’ll show you exactly where your system is leaking.
Fremont’s alluvial Bay Mud and creek-bed silt soils produce a dust and pollen load that pulls into duct systems differently than in cities on firmer ground. Dry summer air makes this dust airborne and recirculating; winter bay moisture can lead to mold growth inside leaky ducts. Sealing the return side and all joints stops this cycle. Our crew accounts for both seasonal loads when we inspect your system.
Yes. These newer units have complex duct geometry with many elbows and shared-wall penetrations that collect construction debris and leak at collars. We use smaller access tools, camera inspection, and precise mastic application to seal every joint without damaging finished surfaces. The work typically takes 2 – 4 hours and is priced as a flat system fee, not per vent.
We start with a camera inspection of the trunk and branch lines, then a pressure test to quantify leakage. We map every joint, collar, and penetration. We note crushed sections, disconnected runs, and signs of moisture or mold. Then we clean under negative pressure with HEPA filtration, seal with mastic and metal tape, and pressure-test again to confirm the fix. You get before photos, after photos, and a written report.
NADCA, the National Air Duct Cleaners Association, sets the cleaning and access standards we follow before any sealing work begins. We don’t seal over dust and debris. We source-remove contamination first, under controlled negative pressure, then seal clean metal. That sequence matters. Sealing dirty ducts traps moisture and particulate, which accelerates corrosion and mold. We do it by the book, every time.
Ready to stop losing conditioned air into your walls and crawlspace? Call Hollis Air Duct Cleaning at (361) 326-5060 for a free estimate on duct sealing in Fremont. We’ll inspect your system, show you the leaks, and give you a written price before any work starts. Every seal is backed by our 365-Day Done Right Promise.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Fremont and the East Bay.