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.
Guardsman Duct Sealing & Repair: The Miami Owner’s Guide
If you have a Guardsman duct sealing or repair component that’s failed, we stock and install Guardsman-compatible replacement parts across Miami, with most jobs running between $350 and $1,200 installed depending on access and the extent of the seal failure. We keep common Guardsman seals, collars, and mastic kits on the truck, so the majority of Miami jobs are done in a single visit. Most homeowners discover the problem the same way: a room that won’t cool properly, a musty smell that won’t quit, or a visible gap where the duct meets the plenum that’s been bleeding conditioned air into a hot Miami attic.
A quick note on how we fit into the picture: Hollis Air Duct Miami is an independent service provider. We’re not affiliated with Guardsman directly, but we install and repair their duct sealing systems alongside parts from Lennox, Trane, and Carrier. Roy Castellanos keeps a straightforward standard for this work: if the seal isn’t right, the air you paid to cool is going somewhere you didn’t pay to cool.
Which Guardsman Models This Applies To
Guardsman’s duct sealing line covers several series, and the compatibility details matter more than most people expect. The most common units we see in Miami homes are the GS-Flex series (flexible duct collars and takeoffs), the GS-Rigid line (sheet metal duct connections and plenum boots), and Guardsman’s water-based duct mastic, which gets applied at every joint where two duct sections meet. The fastest way to identify what you have is to look at the label on the duct collar or the bucket of mastic. Guardsman prints the series code right on it: GS-Flex, GS-Rigid, or GS-Mastic, followed by a size designation in inches.
Here’s the compatibility gotcha that trips up Miami homeowners: Guardsman collars are sized to the outside diameter of the duct, not the inside. If you measure the inside and order that size, the collar won’t seat. We measure both ways on every job and confirm before anything gets ordered. For the OEM-versus-aftermarket decision, we’re direct about it: Guardsman’s OEM seals and collars are well-made and we stock them when the model calls for it, but for older GS-Flex series where OEM stock is spotty, we use aftermarket equivalents that meet the same spec, and we tell you which one is going in before we start.
Styles & brands we work with
Signs Your Guardsman Duct Sealing & Repair Is Failing
- One room that never cools down. A failed duct seal lets conditioned air escape into the attic or wall cavity before it reaches the register. The room at the end of that duct run is the first to feel it, especially on the west side of a Miami house in August.
- Higher electric bills with no change in habits. When your duct system leaks, your AC runs longer to hit the thermostat setting. In Miami, where AC runs hard from May through October, a 20% duct leak shows up as a bill that climbs while the thermostat stays put.
- A musty odor that comes and goes with the AC. Gaps in duct seals pull humid attic air into the system when it cycles on. That’s condensation, then mold, then the smell. We see this pattern constantly in Coral Gables and Coconut Grove homes where older mastic has cracked.
- Visible gaps or cracked, peeling material at duct joints. Guardsman’s mastic and collar seals dry out over time, and South Florida’s heat and humidity accelerate it. If you can see daylight or feel air moving at a joint, the seal is done.
- Dust accumulating fast around registers. A negative-pressure leak pulls attic dust and insulation into the duct stream. If your registers are collecting gray fuzz a week after cleaning, the leak is upstream of the register.
Replacement Cost & What’s Included
Installed Guardsman duct sealing and repair in Miami typically runs $350 to $1,200, and the range breaks down simply. Resealing one or two accessible joints with Guardsman mastic runs $350 to $550. Replacing a failed GS-Flex collar or takeoff with parts and labor lands between $450 and $700. A full reseal of all accessible duct joints in an average Miami single-story home, including attic access and multiple plenum connections, is the $800 to $1,200 job. What drives the difference is access: a closet utility chase is quick; a low-pitch attic with blown insulation takes longer.
We write the price before we touch anything, and it does not move at the door. That price includes the Guardsman or spec-matched aftermarket part, the mastic or sealant, labor, and cleanup. Every repair we make is covered by the 365-Day Done Right Promise: if the seal fails within a year, we return and fix it at no charge.
See the difference
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After
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After
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AfterDIY or Call Us?
What you can safely check yourself: look for visible gaps at duct joints, feel for air movement around collars while the system runs, and check for cracked or peeling mastic. That inspection costs nothing and tells you whether you have a real problem. What you should not attempt yourself: open a pressurized duct run and start resealing. Duct sealing requires working in tight attic spaces with the system off, proper mastic application, and knowing which leaks actually matter for airflow. A bad DIY seal job can create more leaks than it fixes, and you’ll be back in the attic in six months.
The bigger issue is honesty: if you reseal the visible joint but miss the one behind the plenum, you’ve spent an afternoon and still have the electric bill problem. Call us at (850) 660-3272 and we’ll give you a straight assessment with a written price. Roy’s rule for this kind of call is simple: if you can’t explain the job plainly, you probably shouldn’t be doing it.
FAQs
Guardsman duct seals typically last 12 to 15 years in Miami’s climate, but we see failures as early as 8 years in attics with poor ventilation where heat and humidity sit on the mastic all day. The seal material degrades faster when attic temperatures stay above 120°F for months, which is common in Miami summers. If your system is past the 10-year mark, an inspection is worth the call.
Most failed Guardsman seals can be repaired by scraping the old mastic and applying fresh material to the joint, but a cracked collar or split in the GS-Flex boot needs full part replacement. We’ll tell you which one you’re looking at before we quote it, because the repair path and part path are different prices. Call (850) 660-3272 and we can often diagnose it over the phone with a few photos.
A single-joint reseal or collar replacement takes 1 to 2 hours, and a full accessible reseal of an average Miami home runs 3 to 5 hours including attic access and cleanup. We arrive inside the quoted window, and the job is done the same visit in nearly every case.
We keep common GS-Flex collars, GS-Rigid boots, and Guardsman mastic on the truck, which means most Miami jobs don’t wait on an order. If your model needs a less common part, we order it and return as soon as it lands, with the price locked at the original written quote.
In business since 2004 – part of the Garrison Partners family with a track record that predates most local competitors.
When your Guardsman duct sealing system has failed, the fix is a part matched to your model, priced before work starts, and backed in writing. We answer the phone 24/7, and the person you talk to can give you a straight answer about what you’re looking at. Call (850) 660-3272 for a free estimate on your Guardsman duct sealing and repair in Miami.
Written by Roy Castellanos, Owner, Hollis Air Duct Miami at Hollis Air Duct Miami, serving Miami and nearby areas.