Fast, Reliable Duct Repair & Sealing Across Miami
Duct repair and sealing in Miami typically costs $280-$650 for most residential jobs, with flex duct replacement running $180-$340 per section and full metal trunk line restoration reaching $800-$1,400. We answer calls live 24 hours a day, and most Miami repairs are completed in a single visit. Call (844) 685-6342 for upfront pricing before we lift a single tool.
We’ve worked the attics of Miami for over 42 years, from the concrete block homes of Little Havana to the mid-century builds near Coral Gables. We know what 140°F attic heat does to flex duct. We know how salt air creeping through soffit vents corrodes metal trunk lines from the inside out. And we know that in Miami, your AC never gets a day off, which means your ductwork never gets a chance to dry out. That’s not a theory for us. It’s what we see Monday through Saturday, and on emergency calls Sunday too.
Our technicians are background-checked, uniformed, and equipped with Rotobrush agitation systems and HEPA vacuums. Every job gets a camera inspection before and after, so you see what we see. No claims without proof.
Why Bellows Air Duct & Vent Co. Is Miami’s Preferred Duct Repair & Sealing Company
We’ve been at this since 1984, named for the oldest air-moving tool there is. That longevity means something in Miami, where we’ve watched three generations of homeowners in the same 33142 and 33143 ZIP codes call us back for the next problem because we didn’t create one the first time.
Our phone is answered by a live person, 24/7. Not a voicemail tree, not an app. When your AC is pushing 85°F air because a duct joint separated in the attic, you want a human who can dispatch a crew, not a chatbot promising a callback.
Our 90-Day Done Right Promise is stamped on every job. If it’s not right, we return at no charge. No paperwork, no arguing. We’ve honored that for 42 years without a single complaint to the Better Business Bureau that wasn’t resolved the same day.
We know Miami’s building stock. The 1950s-1970s concrete block and stucco homes in this corridor, from West Miami to Sweetwater to the UM fringe, share a common flaw: original flex ductwork running through unconditioned attics that routinely hit 140-160°F in July and August. We’ve resealed hundreds of those joints. We’ve replaced miles of degraded insulation. And we’ve learned which fixes last and which ones don’t.
Our Duct Repair & Sealing Services in Miami
Duct Sealing
Miami’s subtropical humidity means condensation forms on cool duct surfaces whenever a system short-cycles or a seal fails. Standing moisture feeds black mold within days, not weeks. Our duct sealing starts with a camera inspection to locate every leak, then we apply mastic sealant, not tape, to joints and connections. Mastic remains flexible through decades of thermal cycling in Miami’s 140°F attics. We seal supply and return plenums, register boots, and trunk line connections. After sealing, we pressure-test to verify results. The goal is simple: conditioned air stays in your ducts, and hot, humid attic air stays out.
Flex Duct Repair
Flex duct fails differently in Miami than anywhere else we work. The extreme attic heat degrades the plastic liner and insulation wrap, causing neck separation at joints and sagging between supports. Once a joint separates, 150°F attic air and blown fiberglass particles pour directly into your return stream. In a West Miami home off SW 8th Street, our crew found exactly that: a 1968-era flex duct joint separated in the attic, dumping unfiltered attic air into the living space. We re-sealed the joint with mastic, replaced 12 feet of degraded flex with R-8 insulated duct, and installed a Honeywell UV air purifier to prevent future mold growth. Most flex duct repairs in Miami run $280-$520.
Metal Duct Repair
In Miami’s coastal neighborhoods like Little Havana, 1960s-era galvanized steel trunk lines corrode from the inside out due to near-constant humidity and salt air in unconditioned attics. This creates a unique composite of rust scale and mold that demands dual-action cleaning. Our technicians resolve this with Rotobrush agitation and HEPA vacuuming, then repair or replace corroded sections with properly insulated metal duct or transition to modern flex where appropriate. We never leave bare metal exposed in a Miami attic; that’s an invitation to condensation and repeat failure. Metal duct restoration in Miami typically ranges from $650-$1,200 depending on linear footage and access difficulty.
Duct Insulation
When attic heat degrades duct insulation, bare duct walls become condensation magnets. In Miami’s 70%+ relative humidity, that’s a mold colony starting within 72 hours. We install fresh R-8 insulation on flex duct and apply closed-cell foam or fiberglass wrap to metal lines, with vapor barriers facing the correct direction for our climate. Proper insulation doesn’t just save energy. In Miami, it’s mold prevention.
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 Miami
We carry professional-grade equipment from Rotobrush, Nikro, and Honeywell, the same brands serious HVAC contractors specify for Miami’s demanding environment. Our trucks stock R-8 flex duct, mastic sealant, and corrosion-resistant hardware so we’re not making supply runs while your attic stays open. That means most jobs finish in one visit. We also install Honeywell and Aprilaire air purifiers and UV systems where mold recurrence is a concern, common in homes near Biscayne Bay where dewpoint temperatures stay elevated even in winter.
Common Duct Repair & Sealing Problems We See in Miami Homes
- Flex duct neck separation in 140°F attics. The plastic liner hardens and cracks after years of thermal cycling. Joints pull apart. Sagging duct rests on attic insulation, compressing it and creating new hot spots. We find this in virtually every 1960s-1970s home in Allapattah and Gladeview.
- Metal duct corrosion from interior moisture and salt air. Galvanized steel trunk lines in coastal Miami neighborhoods develop rust scale from the inside out, a pattern rare in drier Sun Belt cities. The rust flakes off and circulates through your home, while the thinned metal eventually leaks.
- Insulation degradation exposing bare duct walls. Miami’s extreme attic heat breaks down the adhesive and vapor barrier on older flex duct insulation. Once the inner liner is exposed, condensation forms on every cooling cycle. Within a week, you’ve got mold.
- Return plenum leaks pulling unfiltered attic air. The large return plenum in your air handler closet often has untaped seams or missing access panel gaskets. In Miami’s dusty, humid attics, that’s a direct path for fiberglass particles, mold spores, and hot air into your breathing space.
Pricing for Duct Repair & Sealing in Miami, FL
We show you the exact price before we start. No bait coupons, no changes at the door. Here’s what duct repair and sealing costs in Miami’s market:
| Service | Typical Range in Miami |
|---|---|
| Flex duct repair (per section, up to 10 ft) | $180-$340 |
| Flex duct replacement with R-8 insulation | $280-$520 |
| Mastic duct sealing (whole system) | $450-$780 |
| Metal trunk line repair/replacement | $650-$1,200 |
| Duct insulation replacement | $320-$580 |
| Return plenum resealing | $220-$380 |
Final cost depends on linear footage, attic access difficulty, and whether we’re working around existing HVAC equipment. Homes in Brownsville and West Little River with tight truss spacing or blown-in insulation coverage take longer to navigate safely. We factor that into our upfront quote, not into a surprise add-on.
We currently offer $50 off any repair over $250, a free second opinion on any written estimate, and a permanent 5% senior and veteran discount. Call (844) 685-6342 for your exact quote; estimates are free.
We Also Serve Cities Near Miami
Our Duct Repair & Sealing in Miami coverage extends to Allapattah, Brownsville, Gladeview, and West Little River. Same live-answer phone, same 90-Day Done Right Promise, same upfront pricing. If you’re in the 33142, 33143, 33101, or 33102 ZIP codes, we’re your local crew.
Serving Miami, FL - Our Local Coverage Area
We’re based in the Miami 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 Miami
Condensation forms on duct surfaces within hours of a seal failure, not weeks, and mold colonizes in days rather than months. In Phoenix or Las Vegas, a small leak might go unnoticed for a season. In Miami, with year-round AC operation and 70%+ relative humidity, there’s no dormant period to interrupt mold growth. We use mastic sealant rated for wet conditions and always verify seals with pressure testing. Call (844) 685-6342 if you suspect a leak; waiting costs more here than anywhere.
Galvanized steel trunk lines with interior rust scale combined with live mold, plus flex duct joints that have separated after decades of attic heat exposure. The steel corrodes from the inside out due to salt air and constant humidity, a pattern almost unique to coastal Miami. Our Duct Repair & Sealing team addresses both problems with Rotobrush agitation, HEPA vacuuming, and corrosion-resistant replacement materials.
Yes, and those are the majority of our Miami calls. The 1950s-1970s homes in this corridor have flex duct running entirely through attics that hit 140-160°F. We work safely in those conditions, replacing degraded insulation, resealing joints with mastic, and adding support straps where sagging has compressed the duct. Most Coral Gables fringe repairs are completed in one visit.
We recommend a camera inspection every two to three years for homes within three miles of the coast, and every three to four years for inland Miami neighborhoods. Salt air accelerates metal corrosion, and the constant AC operation means any new leak is actively pumping humid air into your system 365 days a year. Our $89 Seasonal Tune-Up includes a basic duct inspection; that’s the most cost-effective way to catch problems early.
Yes. A typical Miami home loses 20-30% of conditioned air to attic leaks, which means your system runs longer to hit thermostat setpoints. Sealing those leaks and repairing separated joints restores that lost capacity. We’ve measured 15-25% reductions in cooling runtime after proper sealing in West Miami and Sweetwater homes. Less runtime means less wear, lower bills, and less moisture stress on your equipment. Call (844) 685-6342 for a free estimate; we’ll show you the leaks before we quote the fix.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Miami since 1984.