Fast, Reliable Duct Repair & Sealing Across Chinatown
Duct repair and sealing in Chinatown typically runs $280-$650 for most residential jobs, with same-day service available when you call before noon. We’re familiar with the tight access, shared chases, and mixed-use buildings that define this neighborhood, and our technicians carry the tools and materials to finish in one visit.
We’ve been driving to Chinatown since 1984. We know the parking situation on Stockton Street, the narrow staircases off Grant Avenue, and the reality of working in buildings where a residential unit sits directly above a kitchen running four wok burners and a char siu oven. That local knowledge matters when we’re hauling equipment up three flights or sealing a duct chase that serves six units. If your vents are pushing cooking odors, your energy bills have climbed, or you’ve spotted mold around registers, call us at (844) 685-6342. We’ll answer live, day or night, and give you an upfront price before we start.
Why Bellows Air Duct & Vent Co. Is Chinatown’s Preferred Duct Repair & Sealing Company
Chinatown homeowners call us back because we show them the problem before we fix it. Every job starts with a camera inspection - you’ll see exactly what we’re seeing inside your ducts, whether it’s corroded metal, separated flex, or grease-soaked insulation. No guessing, no scare tactics.
Our 90-Day Done Right Promise applies to every Chinatown job we do. If the seal doesn’t hold, if a joint opens up, or if you’re still getting odors from the restaurant downstairs, we return and make it right. No paperwork to fill out, no argument. Ray Castillo put that in writing when he founded this company, and we still honor it the same way.
Calls are answered by a live person, 24 hours a day. Not a voicemail tree, not an app. When you’re dealing with a duct leak that’s spilling grease-laden air into your bedroom at 10 p.m., you talk to someone who can dispatch a technician.
Our pricing is disclosed upfront, before we lift a tool. The number we give you on the phone is the number on the invoice. We don’t bait you with a low coupon and then add charges at the door. That’s been our practice for over 42 years, and it’s why Chinatown residents who’ve been burned by discount operators stick with us.
Our Duct Repair & Sealing Services in Chinatown
Duct Sealing
Sealing is often the most cost-effective fix in Chinatown’s older buildings, where retrofit ductwork was run through unlined masonry chases never designed for HVAC. We use mastic sealant and reinforced mesh at joints and seams, applied after we remove any grease buildup that’s preventing adhesion. A typical duct sealing job in Chinatown runs $280-$450 for a one-bedroom unit, $400-$650 for larger apartments with longer duct runs. We sealed a leaking flex duct in a Ross Alley apartment above a roast duck shop, where the duct was coated in tacky aerosolized grease that had corroded the aluminum tape joints. We replaced the section with insulated metal duct sealed with mastic to prevent future grease-laden air infiltration.
Flex Duct Repair
Flex duct is common in Chinatown’s post-1906 rebuild apartments because it’s easy to thread through tight spaces. But the combination of marine fog moisture and grease particles from commercial kitchens accelerates mold growth inside the liner. We replace collapsed, torn, or mold-compromised flex with new insulated runs, properly supported to prevent sagging that traps condensation. Most flex duct repairs in Chinatown fall between $320-$520.
Metal Duct Repair
Metal ductwork in Chinatown corrodes faster than you’d expect. Grease-laden air from ground-floor restaurants rises through shared ventilation shafts and eats at galvanized steel, especially at joints and seams where condensation collects. We cut out corroded sections, fabricate replacements on-site, and seal with mastic rather than tape, which grease degrades within months. Metal duct repair in Chinatown typically costs $380-$620 depending on access and extent of corrosion.
Duct Insulation
We replace duct insulation that’s yellowed and tacky with aerosolized cooking grease - grease that didn’t come from your kitchen but from the BBQ pork shop on the ground floor, drawn up through an unlined chase over many years. New insulation with a proper vapor barrier stops condensation, improves efficiency, and blocks odor transfer. Duct insulation replacement in Chinatown runs $340-$580 for standard residential runs.
What happens when you call
- 1
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.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Chinatown
We stock parts and materials from Abatement Technologies, Aprilaire, and Rotobrush on our Chinatown service vehicles, which means most repairs are completed in a single visit without waiting for a warehouse run. That matters when you’re dealing with a grease-compromised duct in a building where parking a second time means circling for twenty minutes. We also specify Guardsman corrosion-resistant fasteners and hardware for coastal environments where standard materials fail early. If your system uses Honeywell or Nikro components, we carry those too. Our technicians are trained on the full range, so you’re not getting a generic fix on a brand-specific system.
Common Duct Repair & Sealing Problems We See in Chinatown Homes
- Grease corrosion at metal duct joints. The aerosolized grease rising from commercial kitchens attacks galvanized steel faster than plain moisture. We see pinhole leaks and separated seams in ducts that are only eight to ten years old, well short of normal lifespan.
- Mold inside flex duct from the fog-grease combination. Chinatown’s persistent marine fog keeps humidity high, and when grease particles coat the inside of flex duct, they create a nutrient film that mold colonizes quickly. The musty smell many residents blame on old carpet often originates here.
- Air leakage through unlined chases. Ductwork retrofitted through original masonry chases was never meant to be airtight. We find significant leakage where flex connects to metal, or where metal passes through chase walls, drawing cooking air and odors between units.
- Collapsed or sagging flex duct in tight crawlspaces. Chinatown’s narrow buildings leave little room for proper support. Flex duct that isn’t hung correctly sags, collects condensation, and eventually tears at the low point.
Pricing for Duct Repair & Sealing in Chinatown, CA
Here’s what duct repair and sealing costs in the 94133 market:
| Service | Typical Range |
|---|---|
| Duct sealing (mastic, residential unit) | $280-$450 |
| Flex duct repair/replacement | $320-$520 |
| Metal duct repair (section replacement) | $380-$620 |
| Duct insulation replacement | $340-$580 |
| Full duct sealing with camera verification | $450-$750 |
Three factors push costs toward the higher end: access difficulty (tight chases, multiple flights of stairs), extent of grease contamination requiring pre-cleaning, and whether we’re working in a shared chase that requires coordination with building management. We disclose your exact price before starting, and our $50 Off Any Repair Over $250 applies to jobs over that threshold. Seniors and veterans receive a permanent 5% discount. Call (844) 685-6342 for a free estimate - we’ll give you a firm number, not a range that doubles once we’re inside.
We Also Serve Cities Near Chinatown
Our Duct Repair & Sealing in Chinatown team is based in San Francisco and covers the full metro area, including the Mission District, Noe Valley, and Daly City. Same live-answer phones, same upfront pricing, same 90-Day Done Right Promise. If you’re in a bordering neighborhood and unsure whether we service your building, call and we’ll tell you straight.
Serving Chinatown, CA - Our Local Coverage Area
We’re based in the Chinatown 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 - Duct Repair & Sealing in Chinatown
The odor comes from grease-laden air drawn up through shared ventilation chases from ground-floor restaurants, not from your own cooking. Standard duct cleaning removes surface buildup but doesn’t seal the leaks that allow that air to enter your system. We address this with mastic-sealed joints and, where needed, replacement of unlined chase sections with proper ductwork that isolates your airstream. Call (844) 685-6342 and we’ll camera-inspect to find the exact entry points - estimates are free.
Yes. We work in shared chases regularly in Chinatown’s mixed-use buildings and coordinate access through building management or the HOA. Most repairs are done from within individual units, accessing the chase at connection points without entering neighboring apartments. When common-area access is needed, we schedule with the building and work efficiently to minimize disruption. Call (844) 685-6342 to discuss your building’s specific layout.
Every 5-7 years for buildings with active commercial kitchens below residential units, compared to 10-15 years in conventional residential construction. The grease-moisture cocktail in Chinatown’s shared chases degrades seals and tape faster than normal wear. We recommend a camera inspection at year five to catch joint separation before it becomes an odor or mold problem. Our $89 Seasonal Tune-Up includes a visual duct assessment if you’re unsure of your system’s condition.
Mastic outlasts tape by years in grease-exposed environments. Aluminum foil tape, the standard quick fix, degrades when grease condenses on it - we’ve peeled off tape that turned to mush in eighteen months. Mastic forms a flexible, permanent bond that grease doesn’t penetrate, and we reinforce it with embedded mesh at stress points. For Chinatown’s conditions, we use mastic exclusively on repairs we intend to stand behind. Call (844) 685-6342 for an exact quote on sealing your system - estimates are free.
Metal duct with proper insulation and vapor barrier reduces mold risk significantly compared to flex duct in this environment. Flex duct’s corrugated interior traps grease particles and condensation; smooth metal doesn’t. We typically specify insulated metal for Chinatown replacements, sealed with mastic at all joints. The upfront cost runs 15-25% higher than flex, but the longer service life and reduced mold risk make it the better value here. Call (844) 685-6342 and we’ll show you the condition of your current duct on camera before you decide.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Chinatown since 1984.