Fast, Reliable Duct Repair & Sealing Across Fresno
Duct repair and sealing in Fresno typically runs $180-$650 depending on whether we’re patching a single flex-duct run or resealing an entire metal trunk system, and most jobs are completed same-day. Bellows Air Duct & Vent Co. has been driving out to Fresno from our Los Angeles headquarters since 1984, and we know the difference between a quick mastic touch-up and a full retrofit of a 1960s evaporative-cooler system that’s been baking in a 140°F attic for sixty years. If your vents are blowing dust, your rooms aren’t heating evenly, or your energy bill has climbed without explanation, call us at (855) 401-6006. We’ll answer live, give you an upfront price before we leave the office, and get a background-checked technician to your door in Fresno, Clovis, or anywhere in the 93706-93709 ZIP codes.
Why Bellows Air Duct & Vent Co. of California Is Fresno’s Preferred Duct Repair & Sealing Company
We’ve built our reputation in Fresno the same way we did in Los Angeles: by showing up when we say, doing what we promised, and standing behind it for 90 days in writing. Our Duct Repair & Sealing team has handled everything from sagging flex-duct in Fig Garden villas to rusted metal plenums in west-side tract homes, and Fresno customers keep our number because they never need to call it twice.
Calls are answered by a live person, 24 hours a day. Not an app. Not a callback queue. A real person who can dispatch a uniformed, background-checked technician to your Fresno home, usually same-day. Roger Castañeda, who leads Bellows, started this company in 1984 on the principle that a square deal means one honest price shown before a single tool is lifted. That hasn’t changed.
We carry a 90-Day Done Right Promise on every job. If the seal fails, the flex sags again, or the repair doesn’t hold, we come back at no charge. No paperwork, no arguing. That’s stamped on every invoice we write in Fresno.
Our Duct Repair & Sealing Services in Fresno
Duct Sealing with Mastic Sealant
Mastic sealant is the backbone of lasting duct repair in Fresno, but only when it’s applied right. We’ve opened too many attics in the 93706 ZIP to find mastic peeling off in sheets because a previous contractor skipped the solvent wipe on dusty aluminum duct surfaces. In Fresno’s agricultural environment, that dust isn’t household dirt - it’s alkaline field soil and almond hull particulate that prevents proper bonding. Our technicians clean every surface with denatured alcohol before applying Abatement Technologies mastic, then reinforce high-stress joints with fiberglass mesh. The result is a seal that survives summer attic heat and winter tule fog humidity alike. A typical mastic resealing job on a standard Fresno tract home runs $280-$450.
Flex Duct Repair
Flex duct fails differently in Fresno than anywhere else we work. The original flex runs installed during evaporative-cooler-to-central-AC retrofits in the 1950s-1970s weren’t designed for the static pressure of modern forced-air systems, and they’ve been sagging, kinking, and pulling apart from supply plenums for decades. Attics in central Fresno reach 140°F+ for months each summer, degrading the inner liner and causing the wire helix to relax. We recently repaired a flex-duct trunk line in a 1950s tract home on E Church Ave (93706) where an original evaporative cooler retrofit sagged and disconnected from the supply plenum. The homeowner reported visible dust puffs from vents and unexplained allergy symptoms. We resealed the connection with mastic and reinforced the flex with a metal saddle, then advised swapping the undersized return for a Honeywell media filter cabinet to handle the agricultural particulates. Flex duct repair in Fresno typically costs $180-$340 per run, with full replacement at $400-$650 when the inner liner has degraded.
Metal Duct Repair
Galvanized metal ducts in older Fresno homes develop a specific failure pattern we don’t see in coastal markets. Screw holes and seams rust through during tule fog season when attic humidity spikes, creating invisible leaks that depressurize the system. That negative pressure doesn’t just waste energy - it pulls air from wherever it can, including crawl spaces and wall cavities where Valley Fever spores from endemic San Joaquin Valley soil can be drawn directly into your supply stream. We patch metal ducts with matching gauge galvanized steel, seal with mastic, and pressure-test before we leave. Metal duct repair in Fresno runs $220-$480 depending on accessibility and extent of corrosion.
Duct Insulation
Uninsulated or degraded duct insulation is a silent energy thief in Fresno, where attic temperatures can exceed outdoor air by 40 degrees. We install formaldehyde-free fiberglass duct wrap and reflective bubble-barrier insulation where appropriate, paying special attention to flex-duct runs that pass through unconditioned attic space. For homes with ducts in crawl spaces beneath slab foundations - common in 93705 and surrounding ZIPs - we use closed-cell spray foam or rigid board insulation that doesn’t require raising the floor. Proper insulation can drop cooling costs 15-25% in a Fresno summer, and most insulation jobs run $350-$800 for a typical single-story home.
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.
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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 Fresno
We stock parts and specify equipment from the same brands serious HVAC contractors use: Rotobrush for mechanical agitation and debris removal, Abatement Technologies for containment and mastic application systems, and Honeywell for media filtration upgrades that actually handle Fresno’s particulate load. We don’t show up hoping we have what your system needs. Our trucks carry common flex-duct diameters, metal saddle supports, and mastic in quantities sized for Fresno’s older housing stock, so most repairs finish in a single visit without waiting on a parts run to Clovis or Sanger.
Common Duct Repair & Sealing Problems We See in Fresno Homes
- Original flex-duct runs from evaporative cooler retrofits sag and pull apart in attics hitting 140°F+, bypassing the filter and pulling dusty attic air directly into your supply stream. We find this in central Fresno tract homes built 1945-1975, where the original cooler was swapped for forced-air but the ductwork was never properly supported.
- Screw holes in metal ducts rust through from high humidity during tule fog season, creating invisible leaks that depressurize the system and draw in Valley Fever spores from crawl spaces. These leaks rarely show visible rust on the outside - we find them with pressure testing and camera inspection.
- Mastic seals fail within 2-3 years when applied over dusty aluminum duct surfaces common in old Fresno tract-home systems. Contractors skip proper solvent wiping, and the bond peels in summer heat. We see this constantly on repair calls where “it was just sealed” by another company.
- Pest intrusion through disconnected flex-duct joints is accelerated by Fresno’s extreme attic temperatures, which make ductwork an attractive shelter for roof rats and squirrels seeking cooler spaces. The entry points are almost always at unsupported sag points where the flex has pulled from the collar.
Pricing for Duct Repair & Sealing in Fresno, CA
We’re upfront about numbers because nobody likes a surprise on the invoice. Here’s what duct repair and sealing costs in Fresno’s current market:
| Service | Typical Range |
|---|---|
| Single flex-duct repair/reconnection | $180-$340 |
| Mastic sealant application (standard home) | $280-$450 |
| Metal duct patch and seal | $220-$480 |
| Duct insulation (single-story) | $350-$800 |
| Full flex-duct replacement per run | $400-$650 |
| System-wide pressure test with camera inspection | $150-$225 |
What moves you within these ranges? Attic accessibility, extent of contamination, whether we need P100 respiratory protection for ag-field adjacent homes, and if the original ductwork was properly supported. We disclose your exact price before starting - the number on the phone matches the number on the invoice. Ask about our $50 Off Any Repair Over $250, or our Free Second Opinion if you have a written estimate from another contractor. Senior and veteran discounts are 5%, permanent.
We Also Serve Cities Near Fresno
Our service radius covers Fresno proper plus Old Fig Garden, Clovis, Fowler, and Sanger. Same live-answer dispatch, same 90-Day Done Right Promise, same upfront pricing whether you’re in a 1950s Clovis ranch or a Fowler farmhouse with original metal ductwork.
Serving Fresno, CA - Our Local Coverage Area
We’re based in the Fresno 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 Fresno
If you live in the 93706 ZIP or adjacent to active farmland and have unexplained fatigue, cough, or fever that recurs seasonally, a depressurized duct system could be drawing spores from your crawl space or attic. We pressure-test every system we touch to identify negative-pressure leaks, and we wear P100 respirators as standard protocol in ag-adjacent areas - not as an upsell, but because Coccidioides immitis is endemic to San Joaquin Valley soil. Call (855) 401-6006 and we’ll camera-inspect your ductwork to find the leak point.
Yes, but it requires more than patching. Original evaporative-cooler ductwork in Fresno’s 1940s-1970s housing was sized for high airflow at low static pressure, and central AC needs tighter, smaller ductwork at higher pressure. We typically replace the original trunk with properly sized flex or metal duct, seal all connections with mastic, and upgrade the return path to handle modern filtration. Most retrofits run $1,800-$3,200 for a single-story home. We’ll give you an exact quote after inspection - estimates are free.
Proper sealing stops dust from entering through duct leaks, but it won’t stop what’s coming through your return air intake. For Fresno’s August-October harvest season, we recommend pairing duct sealing with a Honeywell media filter cabinet or Aprilaire air cleaner rated for PM2.5 and agricultural particulates. Sealing alone typically cuts indoor dust loading 30-50%; adding proper filtration addresses the rest. Call for a combined quote - we bundle these jobs regularly.
Yes. We use closed-cell spray foam or rigid foam board cut to fit between joists, secured with mechanical fasteners - no floor disturbance required. In 93705 slab homes with crawl spaces, we also check for condensation on metal ducts during tule fog season, since uninsulated cold metal in humid crawl spaces drips and grows mold. Insulation runs $350-$800 for typical single-story crawl-space systems. We’ll inspect and quote at no charge.
No. In Fresno’s 93706 ZIP and other ag-adjacent areas, Coccidioides immitis - the fungus that causes Valley Fever - is present in soil that becomes airborne during tillage, harvest, and wind events. The CDC and California Department of Public Health recommend P100 protection for disturbance of dust in endemic areas. We don’t charge extra for the respirator itself; if you see a line item, it’s for the additional labor time and disposal protocols required when working in confirmed or likely contaminated environments. It’s the same reason our technicians carry them - not for show, but because it’s a genuine occupational hazard in Fresno that doesn’t exist in our Los Angeles jobs. Ask us to explain any line item when we present your upfront quote.
Ready to stop losing cooled air to your attic and stop wondering what’s in your ducts? Call Bellows Air Duct & Vent Co. at (855) 401-6006 for a free estimate in Fresno. We’ll answer live, schedule you promptly, and show you exactly what we find with camera inspection before any work begins. Done right - and backed in writing for 90 days.
Written by Roger Castañeda, Owner at Bellows Air Duct & Vent Co., serving Fresno since 1984.