Duct Sealing in San Antonio - Tested First, Written Price Second

Fast, Reliable Duct Sealing Across San Antonio

Duct sealing in San Antonio typically runs $450 – $1,200 for a whole-home seal, depending on system size and accessibility, and most jobs finish in a single visit. If your vents blow weakly, your upstairs rooms stay stubbornly hot, or your energy bills have climbed without explanation, you’re probably losing conditioned air through gaps you can’t see.

Call (361) 326-5060

We’ve worked in San Antonio long enough to know the patterns. The flex duct in those 1970s ranch homes off State Road 52 sags in the attic heat. The mastic seals in 1990s tract houses near Quail Hollow crack after a decade of expansion and contraction. And the caliche dust that blows through this part of Pasco County finds every gap, every joint, every place where tape has dried and pulled loose. Our crews dispatch from our South Florida scheduling office and coordinate San Antonio appointments with the same discipline we apply everywhere: arrive inside the window, price in writing before we touch anything, leave the site clean. Call (361) 326-5060 and we’ll get you a written estimate with no pressure to book.

Why Hollis Air Duct Cleaning Is San Antonio’s Preferred Duct Sealing Company

San Antonio homeowners don’t need another coupon in the mailbox promising a $49 duct “inspection” that turns into a hard sell. They need a crew that shows up, tells them exactly what’s wrong, and fixes it for the price written on the estimate. That’s what we’ve built since 2004 as part of the Garrison Partners family.

Our reputation here rests on specifics, not slogans. We seal ducts in Alamo Heights-era homes where original fiberglass runs have turned brittle and porous. We handle the newer subdivisions near San Antonio Boulevard where builders used the cheapest tape and it failed inside five years. Every technician is background-checked, uniformed, and held to The Garrison Code: arrive inside the quoted window, price in writing, complete the job by the book, leave the site clean.

Phones get answered by a live person, 24 hours a day, 7 days a week. No voicemail loops. No callback queues. No waiting until Monday when your AC is bleeding cool air into the attic.

Our Duct Sealing team carries the same professional-grade equipment we use on commercial jobs: negative-air machines from Nikro, rotary brush systems from Rotobrush, and sealing products that meet the standards we’d apply in our own homes. The 365-Day Done Right Promise backs every seal. If it fails, we return and make it right at no charge, including a free second visit. That’s written on every job, not implied.

Duct Insulation in San Antonio

Duct Insulation in San Antonio addresses a problem most homeowners don’t discover until their summer electric bill arrives: the cool air your compressor works hard to produce is warming up before it ever reaches your vents. In San Antonio’s climate, where attic temperatures regularly exceed 130°F and HVAC systems run eight months or more of the year, uninsulated or poorly insulated ductwork can lose 20 – 30% of its thermal energy through the thin walls of the duct itself.

The job involves wrapping existing metal or flex duct with formaldehyde-free fiberglass insulation, securing it with mechanical fasteners and vapor barrier, and sealing every seam to prevent condensation. In San Antonio’s humidity, condensation is the enemy: it breeds mold, degrades surrounding materials, and eventually forces a far more expensive replacement. A typical duct insulation job here runs $600 – $1,800 for a whole-home system, depending on linear footage and attic accessibility.

When Attic Heat Overwhelms Your Ducts

San Antonio’s combination of intense solar exposure and poorly ventilated attics cooks uninsulated ductwork. We’ve measured supply air temperatures dropping 8 – 12°F between the air handler and the vent in homes near Curley Road. Insulation restores that lost capacity without upsizing your compressor.

Vapor Barriers for Humid Conditions

Standard insulation without a proper vapor barrier soaks up moisture like a sponge in San Antonio’s summer humidity. We use products rated for Florida’s climate, with sealed seams that keep condensation on the outside of the barrier where it belongs.

HVAC Duct Sealing in San Antonio

HVAC Duct Sealing in San Antonio closes the gaps, cracks, and failed joints that allow conditioned air to escape and unconditioned air to enter your system. In a typical San Antonio home built between 1950 and 1990, we find 15 – 25% total leakage in the duct system, much of it hidden in walls and attics where homeowners never look. That leakage forces your compressor and air handler to run longer, work harder, and fail sooner, while rooms at the far end of the system never reach the thermostat’s set point.

Our sealing process starts with a pressure test to quantify leakage, followed by manual sealing of accessible joints with mastic compound and specialized tape, then aerosol-based sealant injection for the gaps we can’t reach by hand. A typical whole-home HVAC duct sealing job in San Antonio costs $450 – $1,200, with larger homes or systems requiring extensive repair work toward the higher end.

Pressure Testing Before and After

We don’t guess. Our crews use calibrated fan systems to measure total duct leakage in CFM at 25 Pascals, seal the accessible leaks, then retest to verify improvement. San Antonio homeowners get the before-and-after numbers in writing.

Aerosol Sealing for Hidden Gaps

When ducts run through walls or sealed chases, we inject a non-toxic aerosol sealant that finds and plugs gaps from the inside. This method, developed for commercial buildings, can reduce total leakage by 80 – 90% in San Antonio homes where manual access is impossible.

Trusted Brands We Service in San Antonio

We stock parts and materials from the manufacturers whose equipment we trust in our own homes: Abatement Technologies for containment and filtration, Guardsman for durable sealing compounds, and Rotobrush for mechanical agitation systems that prep duct surfaces before sealing. For San Antonio customers, this means no waiting a week for a specialty order to arrive from Tampa or Orlando. Our trucks carry the common sizes of flex duct, mastic, mechanical fasteners, and insulation needed for same-visit completion on most standard residential systems. When a job calls for something specific, our South Florida office coordinates overnight delivery so we’re not burning your time with return trips.

Common Duct Sealing Problems We See in San Antonio Homes

• Original flex duct sagging in ranch attics. The 1950s – 1980s single-story homes that dominate San Antonio’s older neighborhoods were built with lightweight flex duct that collapses under its own weight after decades in the heat. Sagging creates low points where dust and moisture collect, and the restricted airflow forces the system to compensate with longer run times.
• Builder-grade tape dried and failed in tract homes. The 1990s and 2000s subdivisions near San Antonio’s newer growth used the cheapest foil tape available. After twenty years of thermal cycling, that tape has turned to powder, leaving joints completely open to attic air infiltration.
• Caliche dust accelerating seal degradation. San Antonio’s native caliche soil produces a fine, abrasive dust that infiltrates attic spaces and works its way into duct seams. Unlike organic dust, caliche particles are sharp enough to grind away at tape adhesives and mastic surfaces over time.
• Rodent intrusion in older neighborhoods. In areas like Alamo Heights and Monte Vista, we’ve found ducts compromised by roof rats and squirrels seeking shelter from summer heat. They chew entry holes, nest in insulation, and leave gaps that leak air and circulate contaminants until properly sealed and protected.

Pricing for Duct Sealing in San Antonio, FL

We Also Serve Cities Near San Antonio

Our crews cover the full Pasco and Hernando county area, including San Antonio and the surrounding communities of Wesley Chapel, Dade City, Zephyrhills, and Brooksville. If you’re unsure whether your address falls inside our service radius, call (361) 326-5060 and we’ll confirm immediately. We also handle Air Duct Cleaning in San Antonio and Dryer Vent Cleaning in San Antonio for homeowners who want their full system addressed in one coordinated visit.

FAQs About Duct Sealing in San Antonio