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.
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AfterFast, Reliable Duct Sealing Across Missouri City
We dispatch our Duct Sealing crews to Missouri City from our Houston scheduling office, and we’re typically on-site in Sienna, Riverstone, or the older neighborhoods near FM 1092 within the same day you call. If you’re running the AC constantly from May through September and still can’t get the humidity below 60%, the problem is usually not your unit, it’s the gaps in your ductwork pulling attic air into your living space. Call (361) 326-5060 and we’ll send a uniformed technician with a written price before any work starts.
Why Hollis Air Duct Cleaning Is Missouri City’s Preferred Duct Sealing Company
We’ve been doing this since 2004, and in Missouri City we’ve learned that duct sealing here is different from sealing ducts in drier parts of Texas. The Garrison Standard means we arrive inside the quoted window, price the job in writing before we touch anything, and leave the site clean. Our 365-Day Done Right Promise covers every sealing job in writing: if the seal fails or the humidity problem returns within a year, we come back and make it right at no charge, including a free second visit. Every technician is background-checked and uniformed, and our phones are answered by a live person 24 hours a day, seven days a week. No voicemail loops. No callback queues.
Air Duct Sealing in Missouri City
Air Duct Sealing in Missouri City is the process of closing gaps, disconnected collars, and deteriorated seams in your HVAC duct system so conditioned air reaches your rooms instead of leaking into your attic or crawl space. In Missouri City’s market, a typical residential duct sealing job runs $450 – $1,200 for a single system, depending on how many disconnects we find, whether the home has original galvanized trunk lines or modern flex duct, and whether microbial treatment is needed at the joints.
What We Find in Missouri City Attics
Missouri City sits on expansive Gulf Coastal Plain clay that swells and shrinks with our wet-dry cycles, so slab-on-grade homes shift seasonally and pull flex-duct connections apart at the collar and register boot. That means duct sealing here is often structural, not just an efficiency upgrade. Our Gulf Coast humidity load makes those separated joints prime mold sites, so sealing and microbial treatment usually happen in the same visit. We document everything with post-seal camera photos so you can see the difference.
How We Seal It
We use mastic and fiberglass mesh on flex-duct collars, not tape alone, because tape-only patches fail within a season on shifting Missouri City homes. For corroded galvanized trunk lines in older homes near the city core, we address the metal seams directly before sealing the flex connections. Our equipment includes professional-grade negative-air containment systems from Nikro to protect your home while we work.
Duct Sealing Services in Missouri City
Duct Sealing Services in Missouri City cover everything from spot repairs at disconnected register boots to full-system sealing after source removal cleaning. Most Missouri City homeowners call us after noticing uneven cooling between rooms, musty odors when the AC cycles, or utility bills that climb every summer despite a newer HVAC unit. A typical sealing service here costs $450 – $1,200 per system, with whole-home re-sealing on older properties occasionally reaching $1,500 – $2,400 if galvanized trunk lines need sectional replacement.
When Sealing Follows Cleaning
We often find that a duct cleaning alone doesn’t solve the underlying problem. In Sienna, our crew camera-inspected a 2003 home’s attic system and found the R-8 flex supply runs sagging under their own weight, with three disconnected collars at the air handler and a crushed return behind the platform. After NADCA-standard source removal and negative pressure containment, we sealed the collars with mastic and mesh, re-strapped the runs, and documented with post-seal camera photos. The homeowner’s summer humidity complaints dropped noticeably.
Microbial Treatment at the Joints
Attic heat plus Gulf humidity condenses inside sagging R-8 flex, growing mold at sealed joints that homeowners mistake for dust. When we find active microbial growth during a Missouri City sealing job, we treat the affected areas with EPA-registered products before sealing, then verify with post-treatment inspection. This is not an upsell. It’s what the job requires here.
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 Missouri City
We stock parts and filtration products from Honeywell, Aprilaire, and Abatement Technologies for fast turnaround on Missouri City jobs, so we’re not waiting on a warehouse shipment while your attic sits open. Our sealing mastics and mesh meet the same specs commercial crews use on hospital and school systems. For homeowners in Sienna, Riverstone, or the older neighborhoods off Cartwright Road, that means we can complete most sealing jobs in a single visit without a return trip for materials.
Common Duct Sealing Problems We See in Missouri City Homes
- Expansive clay soil separates flex-duct collars. Missouri City’s slab-on-grade homes shift seasonally as the clay beneath swells and shrinks, pulling apart connections that tape-only patches can’t hold. We see this most in homes built between 1980 and 2005, where original flex has hardened and lost flexibility.
- Attic condensation grows mold at sagging R-8 flex joints. In master-planned communities like Sienna and Riverstone, attic temperatures reach 130°F in July while indoor humidity stays above 60%. Condensation forms on the cool duct surface, and mold colonies establish at the joints. Homeowners smell it before they see it.
- Galvanized trunk lines corrode at seams near the city core. Older 1970s-80s homes in central Missouri City often have original or first-replacement galvanized metal trunks that rust through at the longitudinal seam. Sealing the flex connections alone wastes money if the trunk is leaking at the metal.
- Crushed returns behind air handler platforms. During original construction or later HVAC replacements, installers sometimes compress the flex return duct against the platform edge, creating a restriction that starves the system and pulls attic air through every other gap. We find this in roughly one of every four Missouri City homes we inspect.
Pricing for Duct Sealing in Missouri City, TX
A typical duct sealing job in Missouri City runs $450 – $1,200 for a single system. Spot repairs at two or three disconnected collars fall at the lower end. Full-system sealing on older homes with corroded galvanized trunk lines, or homes requiring microbial treatment at multiple joints, fall at the higher end. Whole-home re-sealing with trunk line sectional replacement on properties near the city core can reach $1,500 – $2,400. We give you one flat price per system, agreed in writing before we start. No per-vent pricing. No invoice that balloons once the van is in your driveway. Call (361) 326-5060 for a free estimate, and we’ll inspect your system with a camera so you see exactly what needs sealing.
We Also Serve Cities Near Missouri City
Our crews work throughout the southwest Houston metro, including Duct Sealing in Missouri City as well as Stafford, Sugar Land, Fresno, and Bellaire. Scheduling and dispatch are coordinated from our Houston office, but the technicians who arrive at your door live and work in this area. They know the local building stock, the local soil conditions, and the local humidity patterns that determine how your ductwork fails.
Serving Missouri City, TX - Our Local Coverage Area
We’re based in the Missouri City 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 Missouri City
Older core homes often have galvanized trunk lines that corrode at the seams, so we must address the metal ductwork before sealing the flex connections. Sienna’s newer construction typically uses all-flex systems where sealing is straightforward collar and boot work. Call (361) 326-5060 for an exact quote on your home, estimates are free.
It will if the smell comes from mold growing at disconnected duct joints where humid attic air meets cool supply air. We treat active microbial growth before sealing, then verify with post-treatment inspection. If the smell persists after sealing, the source is likely elsewhere in the home. Call (361) 326-5060 and we’ll diagnose it with a camera inspection.
The expansive clay beneath Missouri City swells when wet and shrinks when dry, causing slab-on-grade foundations to shift seasonally. That movement pulls flex-duct collars and register boots apart, creating gaps that tape alone cannot seal permanently. We use mastic and mesh at these connections because it flexes with the structure. Call (361) 326-5060 for an inspection if your rooms cool unevenly.
Cleaning removes debris from inside the ducts, but if the collars and boots remain disconnected, your HVAC system pulls dusty attic air through those gaps every time it cycles. In Missouri City’s humidity, that attic air carries mold spores too. Sealing closes the pathway. Call (361) 326-5060 and we’ll camera-inspect to find the leaks.
We do, because that’s when Missouri City homeowners notice the problem most. Our technicians work in shifts, use hydration protocols per The Garrison Code, and complete attic work efficiently with negative-air containment to protect your living space. We schedule early morning starts when possible. Call (361) 326-5060 to book a date that works for your household.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Missouri City since 2004.