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 San Antonio
Duct sealing in San Antonio typically runs $400 – $900 for a whole-house seal on standard residential systems, with most jobs completed in a single visit. If you’re on a rural property outside San Antonio where caliche dust from unpaved roads and live oak pollen load your ducts heavily, you’ll likely need sealing paired with source removal on a yearly cadence rather than the 3 – 5 year intervals common in cooler, wetter metros. Call (361) 326-5060 and we’ll give you a written price before any work starts.
We dispatch from our San Antonio office and serve homeowners throughout the metro, from established neighborhoods inside Loop 410 to ranch properties out past Loop 1604. Our crews know the difference between a 1960s Alamo Heights ranch with original flex duct and a 1990s Schertz tract home with rigid ductboard, and we adjust our approach accordingly. The Garrison Standard means we arrive inside the quoted window, price the job in writing, and leave the site clean.
Why Hollis Air Duct Cleaning Is San Antonio’s Preferred Duct Sealing Company
We’ve been part of the San Antonio home services landscape since 2004 as a Garrison Partners company, and our reputation here is built on showing up when we said we would. Homeowners in San Antonio call us after they’ve dealt with no-shows and price jumps from other outfits. We don’t operate that way.
Our technicians are background-checked and uniformed, and you’ll know who’s arriving before they knock. Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues, no waiting until Monday for a scheduling answer.
The 365-Day Done Right Promise covers every duct sealing job in writing: if the seal fails within a year, we return and make it right at no charge, including a free second visit. That’s not a verbal assurance. It’s on the paperwork you sign before work begins.
We know San Antonio’s housing stock. Much of it consists of 1950s – 1980s single-story ranch homes and 1990s – 2000s tract homes, many with original flexible ductwork prone to sagging, kinking, and debris accumulation. In older neighborhoods like Alamo Heights and Monte Vista, original ductwork often shows signs of rodent intrusion and nesting, a problem made worse by the warm climate. We spot these issues during inspection and address them before sealing, not after.
Duct Insulation in San Antonio
Duct Insulation in San Antonio addresses a specific problem: the hot, humid summers that send attic temperatures well above 130°F, cooking the air inside uninsulated or poorly insulated duct runs before it ever reaches your living space. When insulation degrades or was never properly installed, your HVAC works harder, your bills climb, and rooms stay unevenly cooled. In San Antonio’s climate, this isn’t a minor efficiency loss. It’s a real comfort and cost issue.
We inspect insulation with a thermal camera to find gaps, compression, and moisture damage. Typical duct insulation replacement in San Antonio runs $600 – $1,400 depending on accessible linear footage and whether we’re working in a ventilated attic or a tight crawl space.
Attic Duct Insulation Replacement
Most San Antonio homes built before 1990 have insulation-wrapped flex duct in the attic. The wrap compresses over time, and the tape seals fail. We remove degraded material, seal the duct itself with mastic and mesh, then install new insulation rated for our temperature extremes.
Crawl Space and Encapsulated Solutions
Homes in low-lying areas near the San Antonio River or its tributaries often have crawl space moisture issues. We use closed-cell insulation and proper vapor barriers to prevent the mold and mildew that thrive in humid, dark conditions under older ranch homes.
HVAC Duct Sealing in San Antonio
HVAC Duct Sealing in San Antonio stops the conditioned air you’re already paying for from leaking into your attic, walls, or crawl space before it reaches your rooms. In a typical San Antonio home with original ductwork, 20 – 30% of heated or cooled air escapes through gaps at joints, seams, and register boots. We seal these points with mastic, mesh reinforcement, and mechanical fasteners, then pressure-test to verify the improvement.
A standard residential HVAC duct sealing job in San Antonio costs $400 – $900. Larger homes, complex zoned systems, or properties requiring substantial access work (cutting drywall, navigating tight attics) can run $1,000 – $1,800. We give you the exact number in writing before we start.
Pressure Testing and Verification
We don’t guess whether the seal held. After application, we run a duct blaster test to measure leakage in CFM at 25 Pascals. You see the before and after numbers. This is standard practice under The Garrison Code, not an upsell.
Mastic vs. Tape Applications
Foil tape fails in San Antonio’s attic heat within a few years. We use water-based duct mastic, reinforced with fiberglass mesh at joints and boots, rated for the thermal cycling our climate demands. It’s slower to apply. It lasts.
Trusted Brands We Service in San Antonio
Our San Antonio crews carry professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies, the same tools used in commercial and healthcare settings. We stock filtration products from Honeywell, Aprilaire, and Guardsman for replacement during service calls, which means faster turnaround for San Antonio homeowners and no waiting on parts shipments for standard jobs. When we seal ducts in a Monte Vista vintage home or a new build near Converse, we’re working with gear that meets the specification, not hardware-store substitutes.
Common Duct Sealing Problems We See in San Antonio Homes
- Caliche dust infiltration through failed register gaskets. On rural properties outside San Antonio, caliche dust from unpaved ranch roads finds every gap. We replace degraded gaskets and seal boot-to-drywall connections with mastic, not just caulk that cracks in the heat.
- Sagging flex duct in 1970s – 1980s ranch homes. Original flex duct in San Antonio’s housing stock loses tension and creates low spots where debris and condensation collect. We support and re-strap before sealing, or recommend replacement when sagging is severe.
- Rodent intrusion in older neighborhoods. In Alamo Heights and Monte Vista, we’ve found nests and chewed flex duct in attics. We flag this during camera inspection, remove contaminated material, and seal entry points before applying new mastic.
- Wood heat ash and creosote loading in outbuilding systems. Rural properties with shop or guest house duct systems connected to wood heat pull fine particles that overwhelm standard filtration. We clean these runs with negative-air methods before sealing, or the sealant bonds to debris, not metal.
Pricing for Duct Sealing in San Antonio, TX
Whole-house duct sealing in San Antonio typically runs $400 – $900 for single-story homes up to 2,500 square feet with accessible attic or crawl space ductwork. Two-story homes, complex duct layouts, or systems requiring significant access work range $1,000 – $1,800. Duct insulation replacement adds $600 – $1,400 depending on linear footage and material type.
What moves the price: accessibility (tight attics take longer), extent of pre-existing damage requiring repair, whether we need to cut and patch drywall to reach duct runs, and whether source removal (cleaning) is needed before sealing. We never recommend seal-only on a dirty system. The sealant won’t bond properly, and you’ll be calling someone again within months.
Every Hollis job gets a written price before work begins. No per-vent pricing games, no teaser coupons that balloon at the door. One flat price per system, agreed in writing. Call (361) 326-5060 for a free estimate.
We Also Serve Cities Near San Antonio
Our San Antonio crews regularly work in San Antonio and the surrounding communities of Converse, Universal City, Schertz, and Helotes. Whether you’re inside Loop 410 or out on acreage near any of these towns, we price the job the same way: in writing, before we start, with no surprises at the door.
Serving San Antonio, TX - Our Local Coverage Area
We’re based in the San Antonio 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 San Antonio
Yearly. On the rural fringe around San Antonio, ducts load with caliche dust from unpaved ranch roads and live oak pollen in a single season, so outbuilding and main-house systems need duct sealing and cleaning on a yearly cadence rather than the 3 – 5 year interval common in wetter, cooler metros. Call (361) 326-5060 to schedule an inspection and we’ll give you a written price before any work starts.
Yes. Wood heat pulls creosote and ash particles through the ducts, which can overwhelm standard MERV filters and prematurely foul the blower motor if the run isn’t cleaned before sealing. We always source-remove these contaminants with negative-air methods and rotary brush agitation before applying mastic, or the seal bonds to debris and fails within months.
We inspect for sagging, kinking, and rodent damage first. Original 1950s – 1980s flex duct in San Antonio ranch homes often has low spots where debris and moisture collect even after sealing, so we re-strap and support the runs, replace damaged sections, then seal every joint and boot with mastic and mesh reinforcement. The job isn’t complete until we pressure-test and show you the leakage reduction.
Sealing alone won’t solve a dust-loading problem. San Antonio’s heavy caliche dust and live oak pollen coat duct systems differently than in other Texas cities, and these particles re-enter through unsealed boots and register gaskets as soon as the sealant cures. We combine source removal with sealing so the system stays cleaner after we leave. A seal-only job without cleaning fails within months in this environment.
Yes. We regularly seal and clean duct runs in shops, barn apartments, and guest houses on acreage properties outside San Antonio. These systems often have unique loading profiles, wood heat contamination, and longer service drives, but we price them with the same written upfront approach. Call (361) 326-5060 to discuss your specific setup.
We sealed the sagging flex supply and return ducts in a 1970s single-story ranch outside Loop 1604 near Helotes where a wood stove ran most of the winter and the original ducts were caked with caliche dust and ash. After a camera inspection we used agitation tools and source removal to clear the runs, then sealed every joint and boot along the air handler and reapplied mastic and mesh. The homeowner’s register airflow improved and the visible dust at the returns dropped noticeably within the first week.
Ready to stop losing conditioned air to your attic? Call (361) 326-5060 for a free estimate. We’ll give you a written price before any work starts, and every job is backed by our 365-Day Done Right Promise.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving San Antonio and surrounding communities.