Fast, Reliable Duct Repair & Sealing Across Mountain View
Duct repair and sealing in Mountain View typically runs $280-$650 for most residential jobs, with same-day or next-day scheduling available throughout the 94040, 94041, 94042, and 94043 ZIP codes. We’re Bellows Air Duct & Vent Co., and we’ve been serving Mountain View homeowners since 1984. Our technicians know the crawlspaces beneath the mid-century ranches along Cuesta Drive and the retrofitted AC systems in the Old Mountain View neighborhood. We’ll answer your call at (844) 685-6342 any hour, day or night. A live person picks up.
Why Bellows Air Duct & Vent Co. Is Mountain View’s Preferred Duct Repair & Sealing Company
Mountain View homeowners have called us back for forty-two years because we show up when we say and we stand behind the work. Our Duct Repair & Sealing team drives to Mountain View from our Los Angeles headquarters with stocked trucks carrying Rotobrush equipment, Nikro HEPA vacuums, and Honeywell controls. Most Mountain View jobs finish in one visit.
We answer calls live, 24 hours a day. No voicemail, no app. Our technicians are background-checked and uniformed. Every job gets a camera inspection before and after, so you see what we see. The price we quote on the phone is the price on the invoice. Our 90-Day Done Right Promise means if something’s not right, we return at no charge. No paperwork, no arguing.
Ray Castillo, who leads Bellows, started this company on a simple idea: the oldest air-moving tool is the bellows, and the oldest principle in trade work is doing what you said you’d do. That hasn’t changed.
Our Duct Repair & Sealing Services in Mountain View
Duct Sealing
Mountain View’s marine-layer humidity attacks mastic sealant on retrofitted ductwork. We see this constantly in 1950s-1970s ranch homes in the 94040 and 94041 ZIP codes where AC was added decades after construction. The South Bay fog pushes overnight relative humidity higher than Sunnyvale’s western neighborhoods or Los Altos Hills, causing condensation inside poorly insulated ducts and at floor-level return-air boots. That moisture hardens dust cakes and eventually debonds mastic from metal. Our Duct Repair & Sealing in Mountain View includes full joint inspection, reapplication of professional-grade mastic, and metal-backed tape at high-stress connections. We camera-verify every seal before we leave.
Flex Duct Repair
Flex duct in Mountain View crawlspaces takes abuse. The retrofitted AC runs were often shoehorned through low-clearance spaces under slab-adjacent foundations, and thirty years of storage, pests, and compression have flattened or torn them. We recently repaired a flex duct run in a 1960s ranch on Cuesta Drive in the 94040 ZIP where the original retrofitted AC ductwork had been crushed by a homeowner’s storage boxes in the crawlspace. We replaced the damaged flex with Rotobrush-cleaned, sealed metal duct and applied mastic at the boot connection, restoring airflow to the master bedroom. That’s the kind of fix that lasts.
Metal Duct Repair
Oversized rats and squirrels in the Old Mountain View neighborhood (94041) aren’t the only threat to metal ducts. The scalloped metal from undersized retrofits in slab-adjacent crawlspaces loses integrity at joints after decades of vibration and moisture cycling. Simple sealing won’t hold. We cut out failed sections, fabricate replacement runs from galvanized sheet metal, and seal with mastic and mechanical fasteners. The result is a duct that moves air the way the system was meant to.
Duct Insulation
Unconditioned crawlspaces in Mountain View stay damp year-round. Without proper insulation, that cold metal sweats, degrades surrounding structure, and drops your system’s efficiency. We install foil-faced fiberglass or closed-cell foam insulation around repaired duct sections, paying special attention to boot connections where condensation first appears.
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.
Trusted Brands We Service in Mountain View
We stock parts from Honeywell, Nikro, and Aprilaire on every Mountain View truck. Honeywell zone controls and dampers handle the multi-zone retrofits common in expanded ranch homes. Nikro HEPA equipment cleans before we seal. Aprilaire media filters upgrade return-air paths while we’re in the crawlspace. Because we carry inventory locally, most Mountain View repairs don’t wait for a parts run. Your technician has what the job needs.
Common Duct Repair & Sealing Problems We See in Mountain View Homes
- Mastic debonding from marine-layer moisture. Mountain View’s bay-driven fog keeps crawlspace humidity persistently higher than inland Santa Clara Valley cities. That moisture degrades mastic sealant on 1950s-1970s retrofits, especially at metal duct boot connections. We remove failed mastic, prep the metal, and reapply with proper cure time.
- Animal damage in Old Mountain View crawlspaces. The 94041 neighborhood’s mature trees and established landscaping attract rodents that chew through flex duct insulation, creating massive air leaks. We replace damaged flex with metal where accessible, and we seal entry points we can reach.
- Crushed flex from storage and access. Low-clearance crawlspaces under slab-adjacent foundations weren’t designed for ductwork. Homeowners storing items in these spaces compress flex runs flat. We relocate or replace with rigid metal where the geometry allows.
- Undersized retrofit ductwork. AC added to homes built for forced-air heating alone often uses duct too small for cooling loads. The system runs longer, pressures increase, and joints fail. We resize critical runs and seal properly for the actual load.
Pricing for Duct Repair & Sealing in Mountain View, CA
Here’s what honest pricing looks like in Mountain View’s market:
- Duct sealing (mastic reapplication, joint repair, up to 15 connections): $280-$420
- Flex duct repair/replacement (single run, crawlspace access): $340-$580
- Metal duct repair (section replacement, fabrication, sealing): $450-$650
- Duct insulation (wrap or sleeve, per run): $180-$320
- Mastic sealant touch-up at boot connections (minor, localized): $150-$240
What moves the number: crawlspace access difficulty, extent of moisture damage, whether animals have compromised multiple runs, and if we need to fabricate custom metal sections. We disclose the full price before lifting a single tool. No bait coupons, no changes at the door. Call (844) 685-6342 for a free estimate. We also honor our standing offers: $50 off any repair over $250, free second opinion on any written estimate, and a permanent 5% senior and veteran discount.
We Also Serve Cities Near Mountain View
Our service radius covers Los Altos, Sunnyvale, Palo Alto, and Cupertino. Each city has its own ductwork profile - drier microclimates in western Sunnyvale, newer stock in Cupertino, hillside access in Los Altos - and our technicians adjust accordingly. Mountain View remains our focus here, but neighbors are welcome to call.
Serving Mountain View, CA - Our Local Coverage Area
We’re based in the Mountain View 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 Mountain View
Yes. In Mountain View’s 94035 ZIP, commercial duct repairs at Moffett Field and NASA Ames require federal access credentials and documentation standards not needed in neighboring cities. We coordinate with your facilities contact and comply with base security protocols. Call (844) 685-6342 to discuss scheduling and credential requirements for your building.
The original ductwork was sized for heating only, and retrofitted AC runs were often shoehorned through inadequate crawlspaces with undersized flex. We see this pattern throughout the 94040 and 94043 ZIP codes. The solution is usually resizing critical runs and sealing joints properly for cooling airflow. We’ll camera-inspect and show you exactly where the bottleneck is. Estimates are free - call (844) 685-6342.
Mountain View’s position near the southern end of San Francisco Bay means overnight relative humidity runs higher than inland Santa Clara Valley cities. That recurring moisture causes condensation inside poorly insulated ducts and debonds mastic sealant at metal connections, especially in crawlspaces. We use moisture-resistant mastic formulations and verify cure conditions before closing up. For a crawlspace assessment, call (844) 685-6342.
Yes. We regularly replace rodent-damaged flex duct in the Old Mountain View neighborhood and seal accessible entry points. Where animals have compromised metal duct, we fabricate replacement sections. Every repair includes camera verification. Call (844) 685-6342 to schedule - we’ll inspect and quote before any work begins.
We install Honeywell controls and dampers, Nikro HEPA cleaning equipment, and Aprilaire filtration media. For fabrication, we use galvanized sheet metal and professional-grade mastic from Abatement Technologies. These are the same brands serious HVAC contractors specify, and we stock them on our Mountain View trucks for same-day completion. Call (844) 685-6342 to confirm availability for your specific repair.
Ready to fix the ductwork in your Mountain View home? Call Bellows Air Duct & Vent Co. at (844) 685-6342. We’ll answer live, schedule a free estimate, and show you camera footage of what we’re fixing before we start. One honest price. No surprises on the bill. And if it’s not done right, we’ll make it right for ninety days - in writing, no arguing.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Mountain View since 1984.