Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
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.
Fast, Reliable Duct Sealing Across North Miami
Duct sealing in North Miami typically runs $450 – $1,200 for a whole-house seal on mid-century homes, with most jobs completed in a single day. If your vents blow weak, your bedroom never reaches setpoint, or your energy bill climbs every summer, the problem is likely leaking seams in the original ductwork, not your AC unit itself.
We serve North Miami from our Miami-area dispatch office, and our crews know the local housing stock: the concrete-block ranches from the 1950s through 1970s in Sans Souci and Keystone Point, the low-pitch attics that trap heat and moisture, and the original galvanized metal ducts that Biscayne Bay salt air has been corroding for decades. When you call (361) 326-5060, a live person answers, and we’ll give you a written price before any work starts.
Why Hollis Air Duct Cleaning Is North Miami’s Preferred Duct Sealing Company
We’ve been part of the Garrison Partners family since 2004, and our Duct Sealing team has handled enough North Miami homes to know the difference between a quick register-boot patch and the real seam-and-collar work these houses need. Homeowners here aren’t dealing with new-construction dust; they’re living with 40-year-old duct runs that Hurricane Andrew patched rather than replaced, and salt aerosol that keeps reopening what was sealed last season.
Our technicians are background-checked and uniformed, and they work under The Garrison Standard: arrive inside the quoted window, price in writing, complete the job by the book, leave the site clean. Every repair carries our 365-Day Done Right Promise – if the seal fails within a year, we return and make it right at no charge, including a free second visit. No estimates that balloon once we’re inside. No per-vent pricing games. One flat price per system, agreed before we touch anything.
Phones are answered by a live person 24 hours a day, 7 days a week. If you’re smelling musty air from a Keystone Point attic or fighting a 9-degree temperature split in a Sans Souci bedroom, we know what to look for and we know where to find it.
Duct Sealing Services in North Miami
Duct Sealing Services in North Miami focus on the seam-and-collar failures that generic duct cleaners miss, because mid-century homes here still hide original sheet-metal trunks behind galvanized sleeves, and the worst leaks are inside wall cavities or under low-pitch attic decking where salt air corroded the seams long before the register boots failed. A typical whole-house seal runs $450 – $1,200 depending on accessibility, the extent of corrosion, and whether we’re patching three collar seams or rebuilding a rust-jacked trunk. Most jobs finish in four to six hours.
Leak Detection and Source Identification
We pressurize the system and use smoke pencils and thermal imaging to map the leak path, but in North Miami the critical step is camera inspection of the trunk line. The visible joints at the register boots often test tight while the collar seams inside the wall cavity blow open under pressure. We find the disconnects you can’t see from the living room.

Mastic Sealing with Reinforced Mesh
For corroded galvanized metal, we clean the surface to bare metal under negative pressure, then apply duct-sealing mastic reinforced with fiberglass mesh. On salt-pitted trunk lines, we sometimes need to sleeve the worst sections with new sheet metal before sealing. The goal is a permanent seal, not a seasonal patch that reopens by the next hurricane.

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.
Duct Insulation in North Miami
Duct Insulation in North Miami addresses the condensation and energy loss that follow sealing work, because a tight duct in an unconditioned attic still sweats when attic temperatures hit 140°F and humidity stays above 70% for months. We insulate with formaldehyde-free fiberglass wrap or closed-cell foam sleeves, depending on space constraints in your low-pitch attic. Typical insulation work runs $300 – $800 when bundled with sealing, or $500 – $1,100 as a standalone job in tight attic spaces.
Attic Trunk Line Wrapping
The original galvanized trunks in 1960s North Miami homes gain significant efficiency from proper wrapping, but space is tight under low-pitch decking. We use high-R-value fiberglass with a reinforced vapor barrier, taped at every seam. The wrap stops condensation that would otherwise re-corrode the metal we just sealed.
Flex Duct Sleeve Replacement
Where previous repairs left collapsed or water-damaged flex patches, we replace the entire run rather than patch over mold. New insulated flex, properly supported and sealed at both ends, eliminates the low points where condensate pools after a storm.
Trusted Brands We Service in North Miami
Our trucks carry professional-grade equipment from Nikro negative-air machines and Honeywell filtration components to Aprilaire humidity control products and Abatement Technologies HEPA containment systems. For North Miami’s salt-corroded metal ductwork, we stock galvanized repair sleeves, mastic rated for marine environments, and reinforced mesh that holds against thermal expansion in unconditioned attics. Most parts are on the truck, so we’re not waiting on a supply house while your attic sits open. We explain what we’re using and why, in plain terms, before we start.
Common Duct Sealing Problems We See in North Miami Homes
- Collar seams rust-jacked open by salt aerosol. Biscayne Bay salt air penetrates attic vents and corrodes galvanized metal from the inside out. Mastic pulls away from pitted surfaces within a season unless the metal is properly prepped and sleeved first.
- Hidden trunk disconnects inside wall cavities. Because the original sheet-metal trunk runs inside the concrete-block wall, a leak at the collar seam pressurizes the cavity and pulls attic air through every crack. The bedroom stays warm and musty even when the register blows hard.
- Collapsed flex patches over condensate pools. After hurricane-season power outages, attic humidity spikes and condensate collects at low points in the duct run. Previous flex repairs sag into the water, collapse, and become mold sources that sealing alone won’t fix.
- Original trunks mistaken for return chases. In 1960s homes with multiple renovations, the supply trunk is sometimes buried so deep that a contractor seals only the visible return duct, leaving the real leak untouched and the musty odor persistent.
Pricing for Duct Sealing in North Miami, FL
Whole-house duct sealing in North Miami runs $450 – $1,200, with most single-story homes in the $550 – $850 range. Duct insulation adds $300 – $800 when done together. What moves the price: how many collar seams need attention, whether we can reach the trunk without removing decking, the extent of salt corrosion requiring metal replacement, and whether previous patches have collapsed and need removal first.
We do not quote per-vent prices. We do not offer teaser coupons that jump once we’re inside. We inspect, we write the full price, and that number does not move at the door. Estimates are free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near North Miami
Our North Miami crews also handle jobs in Jacksonville, Miami, Tampa, and Orlando. Each location operates independently under The Garrison Standard, with the same written pricing and 365-Day Done Right Promise.
Serving North Miami, FL - Our Local Coverage Area
We’re based in the North 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 About Duct Sealing in North Miami
Storm-surge humidity and generator-downtime condensation turn attic flex duct into a mold farm, and the musty odor persists because your system is pulling air through a damp, uncapped stub or a collapsed low point in the duct run. We check the low points first, where water pools after every tropical storm. Call (361) 326-5060 for an inspection – estimates are free.
Most original galvanized trunks can be sealed if the corrosion hasn’t perforated the metal, but the prep work matters more than the mastic. We clean to bare metal, sleeve the worst sections, and seal with marine-rated materials. Full replacement is only necessary when the trunk has rusted through at multiple points or the collar seams have disintegrated. We’ll show you camera footage and give you a written price for either option.
We pressurize the system and use smoke pencils at the registers, but the critical tool is a borescope camera fed through the duct or a small attic access hole. In North Miami’s concrete-block homes, the collar seams inside the wall cavity are where we find the real leaks – not at the visible boots. Thermal imaging confirms the temperature split that proves air is escaping behind the drywall.
Sealing stops your system from pulling humid attic air into the supply stream, which directly reduces indoor humidity. But if your ducts are uninsulated, condensation on the cold metal surface adds moisture back into the attic. We typically recommend sealing and insulation together for North Miami homes, because the subtropical climate means year-round condensation risk. Call (361) 326-5060 and we’ll assess which your house needs.
Most whole-house seals run $550 – $850 for a single-story home, with complex jobs on heavily corroded systems reaching $1,200. Price drivers are attic accessibility, the number of seams requiring metal repair, and whether previous flex patches need removal. We write the full price before any work starts, and it does not change. Call (361) 326-5060 for your free estimate.
Ready to stop throwing cool air into your attic? Call Hollis Air Duct Cleaning at (361) 326-5060 for a free, written estimate on duct sealing in North Miami. Our technicians arrive uniformed and background-checked, price every job in writing before starting, and stand behind their work with a 365-Day Done Right Promise. If the seal fails, we come back and make it right at no charge.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving North Miami since 2004.




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