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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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AfterHow Much Does Duct Repair & Sealing Cost in Miami?
Duct repair and sealing in Miami, FL typically costs between $350 and $900 for most homes. Minor repairs like sealing a small leak or replacing a short section of flex duct run $150 to $400, while comprehensive sealing with mastic across an entire system lands between $500 and $1,400. A full inspection with minor repairs included averages $385 in the Miami market.
Those are real numbers we write on estimates every week. Before you call anyone, you should know what drives the price, what’s a fair range for your situation, and what separates a disciplined job from a patch-and-run. That’s what this guide covers.
Key Takeaways
- Most Miami homeowners pay $350 to $900 for duct repair and sealing.
- Sealing a single leak starts around $150; whole-system sealing runs $500 to $1,400+.
- Miami’s humidity and salt air corrode ducts faster than inland Florida markets, which pushes repair frequency up.
- Written pricing matters more in this trade than the quote itself. If a price isn’t in writing before work starts, walk.
- Hollis Air Duct Miami gives free estimates and written pricing on every job. Call (850) 660-3272 to schedule.
Duct Repair & Sealing Cost Breakdown (2026)
Here’s what we’re seeing across Miami homes in 2026, broken down by job type. These ranges reflect actual work in neighborhoods from Kendall and Hialeah up to Miramar and out toward Westchester.
| Service | Price Range | What’s Included |
|---|---|---|
| Duct inspection with minor sealing (up to 2 leaks) | $150 – $385 | Visual inspection, leak confirmation, mastic seal on 1-2 accessible joints |
| Single duct section repair | $200 – $450 | Replacing a damaged flex duct run, reconnecting loose joints, sealing both ends |
| Whole-system duct sealing (mastic method) | $500 – $1,400 | Accessible ductwork sealed at all joints and connections; price scales with home size and duct count |
| Supply or return plenum repair | $300 – $650 | Resealing the box where ducts meet the air handler; includes mastic and fasteners |
| Duct leakage test (diagnostic only) | $150 – $300 | Pressure test to quantify leakage before and after sealing; often credited toward sealing cost if you proceed |
Homes in Coral Gables and Pinecrest with original 1980s sheet-metal ductwork tend to land on the higher side of these ranges. Older metal ducts have more joints, and each joint is a potential leak point. Newer flex-duct systems in Doral or Sweetwater townhomes often need fewer touchpoints, which keeps sealing costs in the $500 to $800 band.
What moves the needle the most is access. If your air handler sits in a tight closet or the duct runs through a low-clearance attic, the labor time climbs. Florida attics run 120 to 140 degrees most of the year, and a technician working in that heat moves slower for safety’s sake. That’s not padding the bill. That’s doing the job without passing out.
What Affects Duct Repair & Sealing Pricing in Miami
- Duct location and accessibility. Ducts in a standing attic are faster to reach than ducts crammed under a low hip roof. Homes in older sections of Little Havana and Liberty City often have tight mechanical closets, and that adds labor time to any repair.
- Number of leaks and their size. A single separated joint at the plenum is a $150 fix. A system with 12 leaking connections scattered across three trunk lines is a different job entirely, usually $800 or more.
- Duct material and age. Sheet-metal ducts from the 1970s and 1980s are still common in Miami’s older housing stock. They seal well with mastic but the number of joints multiplies the work. Flex duct installed in the 2000s typically needs fewer touchpoints but more frequent reconnection at the boots.
- Miami’s humidity and salt air. This is a real cost driver people outside South Florida don’t account for. Salt air from the Atlantic accelerates corrosion on metal collars and fasteners, especially east of I-95. The humidity means condensation sits on seams year-round, which loosens tape over time and encourages gaps at the joints. In Kendall or Doral, you’re sealing to stop energy loss; in Brickell or Edgewater, you’re also fighting the marine environment.
- Mastic vs. tape. Mastic is the correct material for permanent duct sealing, and it costs more in labor than throwing foil tape on a leak. We use mastic because tape fails in Miami’s heat cycling. A homeowner shopping only on price will find cheaper tape jobs. Those jobs don’t hold, and the repair fails within a season or two. Then you pay again.
- Whether the system needs cleaning first. You can’t seal a duct joint covered in 15 years of dust and debris. Mastic won’t bond to a dirty surface. If the ducts need cleaning before sealing, that’s a separate service, typically $300 to $600 for a full system, and it should be quoted as its own line item, not buried in the sealing price.
Duct Repair vs. Duct Replacement: The Miami Math
Here’s the question every homeowner asks, and it deserves a straight answer. In Miami, repairing and sealing existing ducts costs $350 to $1,400. Replacing a full duct system runs $3,500 to $8,000 depending on home size, accessibility, and material.
Repair and sealing makes sense when the duct body is structurally sound and the leaks are at joints, seams, or separated connections. That covers the majority of Miami homes we inspect. Flex duct that’s torn, collapsed, or saturated with condensation needs replacement, not sealant. The same goes for sheet-metal duct with rust holes from salt air.
A rule of thumb that holds up in this market: if sealing can address 80% or more of your leakage at a third of the replacement cost, seal. If multiple duct runs are failing or the insulation jacket is degrading, replacement starts to pencil out, especially in houses where the ducts are 25-plus years old. If you’re weighing both options, a duct leakage test gives you the number to make the call. We’ll run one and show you the results before we quote anything.
For a deeper look at what repair involves in this market, see our Duct Repair & Sealing in Miami page. It walks through the methods, the materials, and what a proper job looks like from start to finish.
Why Duct Sealing Matters in a Miami House
A typical Miami home loses 20 to 30% of conditioned air through leaks before it ever reaches a bedroom or living room register. That’s not an industry talking point. The Department of Energy has published numbers in that range for decades, and pressure tests on Miami homes consistently confirm it.
What that means in dollars: your air conditioner runs longer to hit the set point, your electric bill carries the load, and rooms at the far end of the duct run stay warm in August. Sealing those leaks doesn’t just reduce your bill. It evens out the temperature between rooms and reduces the humidity that sneaks into the system through gaps. That humidity is what feeds mold growth in ducts down here.
One more thing worth stating plainly: the strain from running a system with significant leakage shortens compressor life. A Miami AC unit already works harder than anywhere in the continental U.S. Adding 25% leakage on top of that is how you get a compressor failure in year 7 instead of year 12. The $600 sealing job is cheap compared to a $6,000 condenser replacement.
How to Save on Duct Repair & Sealing
- Bundle the inspection with another service. If you’re already having your ducts cleaned, ask about sealing while the system is opened up. Combines the trip charge and means the surfaces are clean enough for mastic to bond properly the first time.
- Get a leak test before you buy sealing. A $150 to $300 duct leakage test tells you exactly how much air you’re losing and where. That prevents paying for a whole-system seal when the real problem is one failed joint at the plenum.
- Ask for a written, line-item price before work starts. This is the single biggest money-saver in this trade. A written price locks the number. It also filters out the outfits that quote low on the phone and pad once the technician is inside your attic.
- Check for utility rebates. FPL occasionally runs energy-efficiency rebate programs that cover duct sealing. The programs change by season and funding, but it costs you a phone call to check. We can also tell you what’s active when you call.
- Don’t chase the lowest bid. The cheapest duct sealing job in Miami is usually tape on the visible joints, which fails in 18 months. A proper mastic seal costs more once. Paying for it twice is more expensive than doing it right the first time, and the 365-Day Done Right Promise we put in writing means you’re not gambling on that.
Hollis Air Duct Miami gives free estimates. The price we show you before work starts is the price you pay. Call (850) 660-3272 to schedule a walkthrough.
What to Expect from a Hollis Air Duct Miami Sealing Job
We don’t ask you to trust a process you’ve never seen. Here’s what happens, in order, when we do duct repair and sealing in a Miami home.
First, a technician arrives inside the agreed window. Calls are answered by a live person around the clock, so scheduling and confirmation happen by phone with a human, not a callback queue. The technician is background-checked and uniformed. You’ll know their name before they walk through the door.
Second, we inspect the system using the negative-air method where it applies. That’s a setup where a high-powered vacuum (we run Nikro negative-air machines) creates negative pressure inside the ductwork, pulling air through leaks so we can pinpoint exactly where the system is losing air. Paired with a rotary brush system (Rotobrush equipment) when cleaning is part of the job, this shows us the condition of the duct’s interior before we commit to a repair plan.
Third, we write the price down. Every job receives a written price before any work begins. That price does not move at the door, not in Kendall, not in Hialeah, not anywhere.
Fourth, we do the work. The Garrison Code governs how our technicians behave on a job: arrive inside the window, price in writing, complete the work by the book, leave the site clean. Mastic is applied at every accessible joint and seam, connections at boots and plenums are re-secured, and any damaged flex sections are replaced rather than patched over.
Fifth, the work is covered by the 365-Day Done Right Promise. If the repair fails within one year, we return and make it right at no charge. That includes a free second visit. The guarantee is in writing on every job. We don’t do vague “satisfaction guaranteed” language. The terms are specific because that’s how you hold us accountable.
FAQs – Duct Repair & Sealing Cost
How much does it cost to seal ductwork in Miami?
Sealing ductwork in Miami costs $500 to $1,400 for a whole system, and $150 to $385 for minor sealing on one or two accessible leaks. The final number depends on how many joints need work, how accessible the ducts are, and whether the surfaces need cleaning before mastic will bond.
What is the average cost of duct repair?
The average duct repair in Miami runs $200 to $450 for a single section of flex duct or one separated joint. More involved repairs like plenum resealing land between $300 and $650. Most full repair and sealing jobs combined come in between $500 and $900.
Is duct sealing worth the cost?
Yes, when the leakage is measurable. If a duct leakage test shows 20% or more air loss, sealing typically pays for itself within two to four years through lower electric bills in Miami’s cooling-heavy climate. It also fixes room-to-room temperature differences and reduces humidity intrusion that feeds mold.
How long does duct sealing last?
Mastic sealing applied to clean surfaces typically lasts 10 to 20 years in Miami when properly done. Tape-based sealing, especially foil tape subjected to attic heat cycling, fails within 18 to 24 months in this climate. That’s why we don’t use tape as a primary sealant.
Can you come today?
Same-day and next-day appointments are often available depending on the time of year and technician schedule. Miami’s wet season runs May through October and the humidity drives demand for leak detection and sealing. Call (850) 660-3272 and a live person will tell you the first available window.
Contact Hollis Air Duct Miami
If your ducts are leaking, the numbers in this guide give you a clear picture of what a fair price looks like. The next step is a free estimate with a written price you can hold us to. Call (850) 660-3272 and we’ll schedule an inspection at a time that fits your week. Roy Castellanos and the team run every job under The Garrison Standard: show up inside the window, price it in writing, do it by the book, and stand behind it for a full year.
From the home page, you can see the full range of what we do air duct cleaning, dryer vent cleaning, and duct sealing. If you’re in Miami and the air coming through your registers isn’t what it should be, call us. We’ll tell you exactly what it costs before any work starts.
Pricing reflects the Miami market as of 2026. Hollis Air Duct Miami offers free estimates – call (850) 660-3272.
Written by Roy Castellanos, Owner at Hollis Air Duct Miami, serving Miami and surrounding communities since 2004.
What Our Customers Say
"No sales pitch. Told me which parts of the system were fine and only cleaned what needed it."
- Ted L."Careful with the carpet and furniture. Even wiped down the vent covers before putting them back."
- Leo B."Pet hair all through the returns. The crew pulled out a whole bag of it. Smell is gone."
- Ana G.