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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After
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Before
AfterFast, Reliable Duct Sealing Across Berkeley
Duct sealing in Berkeley typically runs $800 – $2,400 for a whole-home system, with most pre-1940 homes falling in the $1,200 – $1,800 range due to access challenges behind original finishes and in slab-embedded runs. We’re usually able to schedule within 3 – 5 business days, and every job starts with a written price that doesn’t move once work begins. If your Elmwood or North Berkeley home still runs on its original gravity furnace, the dust you’re seeing at the registers is almost certainly unsealed joints pulling air from crawlspaces and wall cavities – not a filter problem, and not something a standard duct cleaning alone will fix. Call (361) 326-5060 for a free estimate and camera inspection.
Our crews serve Berkeley from the San Francisco Bay Area office, so we know the hillside streets, the parking constraints around the Claremont district, and the reality of working in basements and crawlspaces built a century ago. We’ve sealed ducts in Craftsman bungalows on Alcatraz Avenue, Mediterranean revivals off Marin Avenue, and mid-century builds in the Berkeley Hills. That local familiarity matters when we’re deciding whether to access ducts through the original redwood wainscoting or find another route.
Why Hollis Air Duct Cleaning Is Berkeley’s Preferred Duct Sealing Company
Hollis Air Duct Cleaning has been part of the Garrison Partners family since 2004, and our Berkeley customers know us for showing up inside the window, pricing in writing, and leaving the site clean. The Garrison Standard requires exactly that, and our 365-Day Done Right Promise backs every seal, joint, and insulation wrap in writing – if it fails, we return at no charge, including a free second visit.
Our technicians are background-checked and uniformed; you know who’s arriving before they walk in. Phones are answered by a live person 24 hours a day, 7 days a week – no voicemail loops, no callback queues. We don’t compete on the lowest teaser price; we compete on discipline. The price we write down before any work starts is the price you pay. No ballooning at the door.
We’ve earned our reputation in Berkeley by understanding what other crews miss: that a 1920s gravity furnace system with ducts embedded in concrete slab or hidden behind original woodwork demands rotary-brush agitation and targeted sealant injection, not just a negative-air machine hooked to a trunk line. That expertise shows up in the results – systems that hold static pressure for the first time in decades.
Duct Sealing Services in Berkeley
Duct Sealing Services in Berkeley address the specific failure modes of pre-1940 housing stock – disconnected runs, crushed returns, and unsealed joints that pull crawlspace air into your living space. We use mastic and mesh reinforcement on accessible joints, flexible sealant injection for slab-embedded runs, and post-job pressure testing to verify the fix. For a typical Berkeley home, duct sealing runs $800 – $2,400 depending on system accessibility and the extent of disconnection; most gravity-furnace systems we see in Elmwood and North Berkeley fall between $1,200 and $1,800.
Slab-Embedded Run Sealing
Berkeley Hills homes with original gravity furnaces often have duct runs encased in concrete slab foundations. Standard negative-air cleaning can’t reach these – the pressure bypasses the blockage entirely. We use Rotobrush rotary brush systems to break up compacted dust, then inject flexible sealant through targeted access points. This preserves the slab integrity while sealing the leak.
Crawlspace Joint Restoration
Unlined metal ducts in Berkeley’s dirt crawlspaces draw soil gases, allergens, and rodent debris through unsealed joints. We disconnect the affected runs, clean with negative-air equipment from Nikro, reseal with mastic, and test before closing. In hillside homes with chronic dampness, we also evaluate whether duct insulation is needed to prevent condensation.
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 Berkeley
Duct Insulation in Berkeley solves a problem the mild marine climate hides: year-round fog dampness and winter rains create condensation on uninsulated metal ducts, especially in crawlspaces and basements with poor ventilation. That moisture feeds mold growth inside the system, and simply sealing over damp ductwork traps the problem. We wrap exposed trunk lines and accessible runs with professional-grade insulation, typically adding $400 – $900 to a sealing job depending on linear footage. Homes in the Berkeley Hills with exposed under-floor runs see the strongest benefit.
Vapor-Barrier Wrapping
Our crews use insulation products from Honeywell and Aprilaire with integrated vapor barriers. This stops warm, humid air from contacting cold duct metal and condensing. In Berkeley’s climate, that’s a year-round concern, not just winter.
Mold-Prone Run Treatment
When we find active mildew inside ducts – common in homes near the fog line – we clean first, then seal, then insulate. Skipping any step guarantees recurrence. We document the condition with before-and-after photos so you see what was there and what we removed.
Trusted Brands We Service in Berkeley
We carry professional-grade equipment and materials from Nikro, Honeywell, and Aprilaire, with Abatement Technologies filtration products on every job. These are the same tools commercial crews use, not hardware-store gear. For Berkeley customers, that means we don’t wait on parts shipments from out of state – our Bay Area warehouse stocks mastic, mesh, insulation wrap, and rotary brush heads in common sizes. Most repairs complete in a single visit. If your system uses older Honeywell or Aprilaire filtration components, we match and replace those during the sealing process rather than leaving you to source them.
Common Duct Sealing Problems We See in Berkeley Homes
- Disconnected runs behind original redwood wainscoting. In Elmwood and North Berkeley Craftsman homes, decades of settling and remodeling have pulled duct joints apart behind walls. Standard negative-air cleaning blows past the gap; sealing requires targeted access and reconnection.
- Crushed returns in dirt crawlspaces. Hillside homes often have crawlspaces too low to stand in, where original metal returns have been crushed by storage, pests, or soil movement. The system pulls crawlspace air directly into your supply. We replace or reshape the return, then seal.
- Slab-embedded ducts with decades of compaction. Berkeley Hills gravity-furnace systems with concrete-embedded runs accumulate dust that rotary brushes alone can break up. Sealing without cleaning first traps that debris; cleaning without sealing leaves the leak.
- Mold inside unsealed, uninsulated trunk lines. The marine climate keeps crawlspaces damp year-round. We find mildew in metal trunks that have never been insulated, especially on north-facing hillsides. Sealing over that growth is malpractice; we clean, dry, seal, and insulate in sequence.
Pricing for Duct Sealing in Berkeley, CA
Whole-home duct sealing in Berkeley typically costs $800 – $2,400. Most pre-1940 homes we work on in Elmwood, North Berkeley, and Claremont fall between $1,200 and $1,800 because of access challenges – original finishes we work around, slab-embedded runs requiring rotary-brush prep, and crawlspace conditions that slow the work. Duct insulation adds $400 – $900 depending on linear footage.
What moves the price: the number of accessible joints versus hidden runs, whether we need to create access through finished surfaces, the condition of existing duct material (rusted metal requires replacement, not sealing), and whether mold remediation precedes the seal. We inspect with a camera before quoting, so the price we write down reflects what we actually found – not a low opener that jumps once we’re inside.
Every estimate is free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Berkeley
Our crews regularly work in Duct Sealing in Berkeley and the surrounding communities: Emeryville, Albany, El Cerrito, and Piedmont. Each shares similar pre-war housing stock and marine-climate conditions, though Berkeley’s concentration of slab-embedded gravity-furnace ducts is unique in the East Bay.
Serving Berkeley, CA - Our Local Coverage Area
We’re based in the Berkeley 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 Berkeley
Yes. We specialize in pre-1940 gravity-furnace systems, including slab-embedded runs and ducts behind original redwood wainscoting that standard crews won’t touch. We use rotary-brush agitation and flexible sealant injection rather than negative-air equipment that misses these hidden runs entirely. Call (361) 326-5060 for a camera inspection and written estimate.
Because cleaning alone doesn’t seal the leaks. If your ducts are disconnected behind walls or pulling air from a dirt crawlspace, the negative-air machine cleaned what it could reach – then your blower immediately recontaminated the system through unsealed joints. We see this constantly in Berkeley Hills homes with original gravity furnaces. Sealing the leaks stops the dust source; cleaning alone is temporary.
Yes. Year-round marine dampness encourages mold and mildew inside unsealed, uninsulated metal ducts. Sealing over damp ductwork traps that moisture and makes the problem worse. In Berkeley, we often clean and dry the system first, seal second, and insulate third to prevent condensation. Skipping any step guarantees recurrence in this climate.
We start with camera inspection to map disconnections, crushed runs, and leak points. Then we use Rotobrush rotary brushes to break up compacted dust in slab-embedded or inaccessible runs. We reconnect separated joints, seal with mastic and mesh, wrap exposed trunks with insulation, and run static pressure tests to confirm the system holds. Before-and-after photos document every stage. For a typical Elmwood or North Berkeley home, this takes one day.
If you see dust streaks on ceiling registers, smell must when the system runs, or notice uneven heating between rooms, you likely need sealing. Cleaning removes accumulated debris; sealing fixes the leaks that let new debris in. In Berkeley’s pre-1940 housing stock, we almost always find both are needed – cleaning first, then sealing, then insulation if dampness is present. Call (361) 326-5060 and we’ll inspect with a camera to tell you exactly what your system needs.
Ready to stop breathing crawlspace air? Call Hollis Air Duct Cleaning at (361) 326-5060 for a free camera inspection and written estimate. Our Duct Sealing team serves Berkeley with background-checked, uniformed technicians, professional-grade equipment, and the 365-Day Done Right Promise – if it’s not sealed right, we make it right, in writing.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Berkeley since 2004.