Whole-home duct cleaning
Dryer vent cleaning
Camera inspection
Sanitizing & deodorizingWhole-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 Key Biscayne
Duct sealing in Key Biscayne typically runs $850 to $2,400 depending on the number of systems and how much of the ductwork is accessible without demolition. Most jobs on the island are finished in a single day, and the work should always include a before-and-after leakage report so you can see what changed. We know Key Biscayne’s housing stock: concrete-block homes with slab-encased ducts from the 1960s and 70s, plus high-rise condos along Crandon Boulevard and Mashta Island where shared return chases pull air from neighboring units. If your ducts are leaking, you’re paying to cool air that never reaches your rooms. Call (850) 660-3272 and we’ll give you a written price before any work starts.
Why Hollis Air Duct Miami Is Key Biscayne’s Preferred Duct Sealing Company
Roy Castellanos leads our crew, and he’s spent years working duct systems in coastal South Florida buildings. He knows what salt air does to metal duct seams on this island, and he knows how to fix it so the repair holds. Our Duct Sealing team arrives in uniform, with background-checked techs whose names you get before they show up. The price is written down before we touch anything, and it does not move at the door. That’s the Garrison Standard, and it applies to every home we work in, from a 1950s ranch near Crandon Park to a newer high-rise off Ocean Lane Drive.
We’re the air duct arm of the Garrison Partners family, in business since 2004. Our 365-Day Done Right Promise covers every sealed joint and repaired run in writing for a full year. If a seal fails, we return and fix it at no charge, including a free second visit. No arguments, no invoice. Key Biscayne homeowners don’t have time for crews that leave a mess or vanish after the check clears. That’s why they also trust us for Key Biscayne Dryer Vent Cleaning. We leave the site clean, show you the camera footage of the sealed seams, and hand you a written report you can keep for your records.
Styles & brands we work with
Air Duct Sealing in Key Biscayne
Air Duct Sealing in Key Biscayne means closing every leak in your duct system, from the air handler connections in the closet or mechanical room to the supply runs that snake through walls, soffits, and concrete slabs. On this island, the job usually starts with a duct leakage test to measure how much conditioned air is escaping. From there, we seal accessible joints with mastic, a paste-like sealant that hardens to a durable, airtight bond, and we use Nikro negative-air equipment and Aeroseal for runs we cannot physically reach, like slab-encased ducts. You get a before-and-after airflow reading so the improvement is documented, not just claimed.
Key Biscayne homeowners call us when their cooling bills climb even though the AC runs constantly, when rooms near the end of long runs stay warm, or when a condo association flags duct issues before a sale. The salt air here corrodes metal duct seams faster than inland. Sealing with a corrosion-inhibiting, moisture-tolerant mastic is the only way to keep those repairs from reopening within months.
Salt-Corrosion Seam Repair
Metal ducts in Key Biscayne age differently than ducts in Miami or Kendall. The constant salt spray off Biscayne Bay and the Atlantic eats at galvanized seams, especially in older concrete-block homes where ducts run through unconditioned soffit spaces. We strip flaking metal, treat corroded joints, and apply a mastic rated for high-humidity coastal environments. Skipping the corrosion control step means paying for the same repair twice.
Aeroseal for Slab-Encased Duct Runs
Many older homes on Key Biscayne have ducts embedded in the concrete slab. Tearing out floors to reach them is not an option. Aeroseal works from the inside: we pressurize the duct system and pump a sealant mist that finds leaks and builds up at the openings, sealing gaps up to five-eighths of an inch. The process takes a few hours and leaves your floors untouched. Afterward, we camera-verify the runs and give you a calibrated flow hood report showing the before-and-after leakage numbers.
Duct Sealing Services in Key Biscayne
Duct Sealing Services in Key Biscayne cover more than patching holes. They include sealing the air handler cabinet, the return plenum, the supply takeoffs, and any accessible branch runs. In high-rise condos, that also means sealing the points where your unit’s ductwork connects to the shared riser so you are not pulling salt-laden, mold-carrying air from the units above and below you. Our Key Biscayne work always includes a written scope, a written price, and a written report after the job is done.
If you own a single-family home with two or three separate AC systems, we seal each system as its own job. Per-system pricing keeps the quote honest and lets you decide which system gets attention first. You always know the full price before the van pulls up.
Whole-Home Sealing Packages
A 2,800-square-foot Key Biscayne home with two systems might run $1,200 to $1,900 for full sealing, depending on duct length and accessibility. A larger waterfront estate with three systems can run $1,800 to $2,400. These are flat, per-system prices, not per-vent add-ons that climb while the crew is on site. You approve the number before we start, and that’s the number on the final invoice.
Condo Resale and Turnover Sealing
Many Key Biscayne condo boards now require documented duct sealing as part of pre-sale inspections, especially in towers along Crandon Boulevard where shared returns make leakage a building-wide issue. We provide a sealed-system report with camera stills and airflow readings that most association boards accept. If your building manager needs a specific format, we’ll adapt the report to match it at no extra charge.
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 Key Biscayne
We work on equipment from Rotobrush, Honeywell, and Guardsman, and we stock the sealants, mastics, and antimicrobial treatments those systems need here in South Florida. That means no waiting a week for a part when the job is already scheduled. Whether your ductwork is original 1968 galvanized metal or newer flex duct from a 2015 renovation, we bring the right materials for the coastal environment. For Key Biscayne homes specifically, we keep corrosion-inhibiting mastic and Aeroseal cartridges on the truck, because we know salt exposure is part of every job on the island.
See the difference
Before
After
Before
After
Before
AfterCommon Duct Sealing Problems We See in Key Biscayne Homes
- Corroded seams reopening after a cheap seal. A standard duct mastic not rated for salt exposure breaks down within months. We use moisture-tolerant, corrosion-inhibiting sealant and back it with the 365-Day Done Right Promise, so if it fails, we come back free.
- Slab-encased ducts leaking into concrete. In older concrete-block homes, ducts run through the slab and leak air into the soil. Aeroseal seals these runs from the inside without cutting into your floors, and we document the leakage reduction with a flow hood.
- Mold growth at duct board joints. Humid island air wicks into fiberglass duct board connections, and the mold weakens the seal and gets pushed into your supply air. We clean the joint, apply an antimicrobial treatment, and reseal with a moisture-resistant mastic.
- Shared condo returns pulling contaminated air from other units. In many Key Biscayne high-rises, sealing only your accessible runs leaves the common riser leaking. We seal the connection points to the shared chase and, when the building allows, treat the run with the same process.
Pricing for Duct Sealing in Key Biscayne, FL
A single-system duct sealing job in a Key Biscayne condo or smaller home typically runs $850 to $1,200. A two-system single-family home falls between $1,200 and $1,900. Larger estates with three systems and long runs run $1,800 to $2,400. The factors that move the price are access, duct length, system count, and whether the runs are slab-encased or behind finished ceilings. There is no per-vent charge and no surprise line item when the crew arrives. Call (850) 660-3272 for a free estimate, and we will give you a written price before any work begins.
We Also Serve Cities Near Key Biscayne
While this page focuses on Duct Sealing in Key Biscayne, our crews regularly seal ducts in Miami Beach condos, Miami single-family homes, and Miami Gardens townhomes. Same written-price standard, same 365-Day Done Right Promise, same crew standards. If you’re across the Rickenbacker Causeway or up in the northern part of the county, call us and we’ll schedule a time that works.
Serving Key Biscayne, FL - Our Local Coverage Area
We’re based in the Key Biscayne 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 Key Biscayne
Salt air attacks metal duct seams and air handler components faster here than almost anywhere else in Miami-Dade. Any seal that isn’t corrosion-inhibiting and moisture-tolerant will reopen within months, especially in homes built in the 1950s through 1970s with original galvanized ductwork. We use materials rated for coastal environments, and the 365-Day Done Right Promise covers every sealed joint in writing. If a seam fails within a year, we return and fix it at no charge. Call (850) 660-3272 to schedule an inspection.
Most Key Biscayne condo boards want a written report showing the before-and-after leakage numbers, camera images of the sealed seams, and a note confirming the connection points to any shared return chase were sealed. We give you all of that on the same day the work is done. If your association has a specific form or format, we’ll complete it at no extra charge. The report stays with the unit, so the next owner has proof the work was performed.
Because each system is sealed, tested, and documented separately. A home with three systems has three air handlers, three sets of runs, and three leakage tests. You are not paying more per system; you are paying for three systems. We price per system so you can see exactly what each one costs and decide which gets scheduled first.
Yes. For slab-encased runs, we use Aeroseal, which seals from the inside by pressurizing the duct system and injecting a sealant mist that finds leaks and builds up at the openings. Your floors and walls stay intact. For accessible runs in soffits or closets, we apply mastic by hand and camera-verify every joint before we call the job done.
Sealing alone will not kill existing mold, but it will stop the moisture entry that lets mold thrive. In humid island air, condensation wicks into duct board joints and feeds mold growth. We clean the affected joint, apply an antimicrobial treatment, and reseal with moisture-resistant mastic so the supply air stays clean. If your condo has a persistent musty smell, call (850) 660-3272 and we’ll inspect the system and tell you honestly what it needs.
Written by Roy Castellanos, Owner at Hollis Air Duct Miami. If you have questions about this page or want a straight answer on your duct system, call us at (850) 660-3272.