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 in Houston: What to Know First
Guardsman duct sealing in Houston typically runs between $450 and $1,200 for a full-system seal, with most jobs completed in a single day. We’re an independent Guardsman service provider, not a factory-authorized dealer, which means we answer to you and your ductwork, not a corporate warranty office. The price is written down before we touch anything, and it does not move at the door.
If you own a Guardsman filtration system feeding into leaking ductwork, call (713) 936-5800 and we’ll give you an exact quote based on what’s actually in your attic.
How Guardsman Products Fail – and How We Fix Them
After well over a decade working Houston attics, we’ve seen every way a Guardsman setup can lose air. Here’s what actually fails and what we do about it.
- Leaky media cabinet seams on Guardsman AirHandler series units. The media cabinet that holds the filtration media pulls apart at the corners after a few Houston summers. Hot, humid attic air gets pulled in downstream of the filter, which defeats the whole point of the system. We remove the cabinet, re-seat it with fresh mastic, and seal the return plenum so the only air moving past that filter is the air it’s supposed to filter.
- Disconnected flex duct at the Guardsman UV-C or media filter housing. We find this in Energy Corridor homes built in the 1990s more often than anywhere else. The flex duct slips off the collar because the original installer used duct tape, and duct tape does not survive a Houston attic. We reattach with screws and seal with a UL 181-rated mastic that holds for years, not months.
- Return-side leaks pulling attic air into Guardsman-filtered systems. This is the failure most Houston homeowners feel but never see. The supply side is sealed, but the return side has a dozen small leaks that pull fiberglass and dust-laden attic air around the filters instead of through them. We smoke-test the return, find every leak, and seal them. This is the repair that makes a Guardsman system actually filter what the box says it filters.
- Cracked plenum connections on Guardsman coil boxes. Houston’s humidity cycle expands and contracts the metal, and eventually the mastic fails at the plenum-to-coil joint. The system starts blowing conditioned air into the attic, which pushes your AC bill up whether you notice it or not. We re-seal the plenum with commercial-grade mastic and re-test static pressure before we leave.
- Improperly seated Guardsman filter media creating bypass. If the media isn’t seated flush in the cabinet, air skirts around it. This isn’t a duct leak in the traditional sense, but it behaves like one: unfiltered air in, filtered air out of the loop entirely. We check the media seat as part of every Guardsman sealing job and correct the cabinet fit or replace worn gaskets.
Styles & brands we work with




Our Guardsman Duct Sealing Process
- 1
Call and book a diagnostic visit. A live person answers at (713) 936-5800, 24 hours a day. We book a window and we arrive inside it, uniformed and background-checked.
- 2
We inspect the system, including the Guardsman filter housing and surrounding duct. We test static pressure, inspect every accessible section from the media cabinet to the supply registers, and note exactly where air is leaving the system.
- 3
You get a written price before we touch anything. This is the Garrison Standard, and it’s non-negotiable. The price we hand you is the price you pay. No “found something else” after the tech is in your attic.
- 4
We seal every joint with a UL 181-rated mastic. For Guardsman housings, we use the same mastic commercial crews run in Houston health-care and office towers. It’s not caulk from a hardware store. It goes on once and stays put.
- 5
We verify the seal with pressure testing. Before we pack up, we re-test static pressure to confirm the system is moving air the way it should. You’ll see the before-and-after numbers, not just a promise that we “fixed it.”
- 6
We leave the site clean and hand you the guarantee in writing. Every Guardsman sealing job carries the 365-Day Done Right Promise: if it fails within a year, we come back and make it right at no charge.
See the difference
Before
After
Before
After
Before
AfterWhat Guardsman Duct Sealing Costs in Houston
Here’s what we charge, in plain terms, for the most common Guardsman scenarios we see in Houston homes.
| Guardsman Scenario | Typical Houston Price Range |
|---|---|
| Full-system duct sealing (single-story, up to 2,000 sq ft) | $450 – $750 |
| Full-system duct sealing (two-story or 2,000+ sq ft) | $800 – $1,200 |
| Guardsman media cabinet re-seal and re-seat (standalone) | $150 – $300 |
| Return-side leak seal only | $250 – $450 |
| Diagnostic visit with pressure testing (credited to the job) | $89 – rolled into your repair |
What moves the price: house size, how accessible the ductwork is in your attic, and whether the leak is isolated or spread across the whole system. If you have a two-story house with the air handler in a finished attic, expect to be on the higher end. Call (713) 936-5800 for a free, written estimate before you decide anything.
Why Houston Homeowners Call Hollis Air Duct Houston for Guardsman Work
Roy Castellanos and his crew have been in Houston attics long enough to know which Guardsman housings fail, where they fail, and how to seal them so they stay sealed. We run on The Garrison Code: arrive inside the window, price in writing, do the work by the book, leave the site clean. Every sealing job carries the 365-Day Done Right Promise, so if the repair fails within a year, we return free. We also service Lennox, Trane, and Carrier systems, which means we know how Guardsman filtration integrates into whatever furnace or air handler is actually moving the air. That’s useful when the leak is at the connection point, and the connection point involves two different brands.
Clean air doesn’t announce itself – you just stop noticing the problem.
FAQs
No, duct sealing does not void a Guardsman warranty, and we use materials approved for HVAC duct systems. We’re an independent Guardsman service provider, not a factory dealer, and we take care to work with existing warranty terms rather than against them. If you have a specific warranty concern, tell us when you call and we’ll address it before any work begins.
Most single-system Guardsman sealing jobs are finished in one day, usually four to six hours from arrival to pressure test. Larger two-story homes or systems with multiple problem areas can run into a second afternoon, but we’ll tell you that up front when we hand you the written estimate.
Duct sealing itself uses mastic and UL 181-rated materials, not Guardsman factory components. If we find a failed cabinet gasket or worn collar that needs replacement, we’ll quote OEM parts when the warranty or fit requires it, and quality aftermarket equivalents when they match or exceed the original spec at a lower cost. You’ll always know which one we’re quoting and why before we start.
We pressure-test the system before and after sealing, and you’ll see the numbers. If air is still escaping where we said we sealed, the 365-Day Done Right Promise applies and we return free. Call (713) 936-5800 for a free estimate and a straight answer about what’s happening in your attic.
In most Houston homes, sealing costs far less than replacement and fixes the actual problem. Duct leaks don’t disappear when you swap the box. If your Guardsman unit is still moving air and the filters are doing their job, sealing is usually the right call. We’ll tell you honestly if replacement is the smarter move, and we’ll quote the seal first so you can compare.
Written by Roy Castellanos, Owner, Hollis Air Duct Houston at Hollis Air Duct Houston, serving Houston and nearby areas.