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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AfterTrusted Duct Repair & Sealing for San Antonio Homeowners
If you’re wondering how much Duct Repair & Sealing costs, prices in San Antonio typically run $280-$1,850 depending on whether you’re sealing accessible joints or replacing collapsed flex runs in an attic. Most jobs we handle in Terrell Hills, Alamo Heights, and Castle Hills are completed in a single visit with a written price agreed before any work starts. Call CleanRun Air Duct Cleaning San Antonio at (726) 600-7155 for a free estimate with no obligation.
Since 2013, we’ve documented the inside of 52,000+ duct systems across Bexar County, and the pattern in San Antonio is consistent: homes built between 2015 and 2025, especially those in Windcrest, Live Oak, and Universal City, frequently show duct leakage rates of 25-40% at the plenum connections and flex duct elbows. That conditioned air isn’t reaching your rooms. It’s pressurizing your attic or crawl space. We’ve photographed collapsed flex duct in Helotes that was dumping $400+ of cooling into a roof cavity every summer, and we’ve found metal duct seams in Leon Valley that had never been sealed with mastic since the original 1987 install. We also provide Duct Repair & Sealing in San Antonio neighborhoods like these. Our crews use Rotobrush and Nikro equipment for diagnostics and repair documentation, and every job leaves with a written price, a 365-Day Done Right Promise, and a photo record of what was found and what was fixed.
What Our Duct Repair & Sealing Service Includes
Duct Sealing
Duct sealing closes the gaps, seams, and connection points where conditioned air escapes your supply ducts or unconditioned air enters your return path. In San Antonio’s climate, with attic temperatures reaching 140°F in July and August, even a 1/8-inch gap at a plenum joint can pull that superheated air into your system. We seal accessible metal seams with mastic sealant (a thick, fiber-reinforced paste that remains flexible for decades) and use UL-181 approved tape at flex duct connections, never standard duct tape, which degrades in Texas heat within 18 months. Every sealed joint is photographed before and after, and the photo is included in your job record.
Flex Duct Repair
Flex duct, the insulated flexible tubing common in San Antonio homes since the 1990s, collapses at elbows, gets crushed by storage in attics, and degrades where it contacts hot roof decking. We replace damaged flex runs with new R-6 or R-8 insulated duct sized to your system’s CFM requirements, supported every 4 feet to prevent sagging, and connected with mechanical fasteners plus mastic, not zip ties. In Kirby and Duct Repair & Sealing - Converse is where we regularly find original flex duct from 2005-2015 installs that has compressed to half its original diameter. The camera shows the restriction before we say a word about replacement.
Metal Duct Repair
Galvanized steel ductwork, still common in Alamo Heights and Terrell Hills homes built before 2000, corrodes at seams, separates at drive cleats, and transmits noise when supports fail. We repair separated sections with S-locks and drives, seal with mastic, and add vibration isolation where furnaces or air handlers have shifted. For rusted sections, we cut out the damaged metal and fabricate replacement pieces on site. Metal duct repair demands precise fitting; a 1/4-inch misalignment creates turbulence that shows up as whistling at your registers.
Duct Insulation
Duct insulation prevents thermal loss as conditioned air travels through unconditioned spaces. In San Antonio, where summer attic temperatures exceed 130°F for weeks at a time, poorly insulated ductwork can raise supply air temperature by 8-12°F before it reaches your vents. We install fiberglass duct wrap with a vapor barrier or replace uninsulated metal with pre-insulated duct board, depending on access and system design. In Selma and Duct Repair & Sealing in Universal City, we’ve measured 95°F air coming out of vents in homes where attic duct had no insulation; after wrapping, the same system delivered 58°F air.
Mastic Sealant Application
Mastic is the industry-standard sealant for permanent duct closure, a water-based compound with embedded fibers that bridges gaps up to 1/4 inch and cures to a flexible, durable skin. We brush mastic onto every metal seam, joint, and penetration in accessible ductwork, applying it thick enough that the mesh reinforcement is fully embedded. Unlike tape, mastic won’t peel in San Antonio’s heat cycles. We use Guardsman-grade mastic compounds rated for 250°F continuous exposure, and we photograph the application wet and the cured result so you can verify coverage.
Air Leak Repair
Air leak repair addresses the unintended pressure imbalances that force your HVAC system to work harder than designed. We pressurize the duct system and use a smoke pencil or theatrical fog to locate leaks invisible to the eye, then mark, photograph, and repair each one. Common leak points in San Antonio homes include the return air platform (where the filter slot meets the furnace), drywall penetrations behind registers, and abandoned duct boots from previous renovations. A typical 2,400-square-foot home in Castle Hills has 12-18 separate leak points; we document every one.
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.
Signs You Need Duct Repair & Sealing Right Now
- Uneven temperatures room to room. If your master bedroom in Windcrest stays 6°F warmer than your living room despite the thermostat setting, restricted or leaking supply duct is the likely cause. The system is delivering the right volume of air to the wrong places, or losing it entirely.
- Dust accumulation immediately after cleaning. You dust on Saturday and by Wednesday the coffee table is coated again. Leaky return ducts in your attic pull fiberglass particles, pollen, and attic debris directly into your air stream, bypassing the filter entirely.
- Whistling or rushing noise at registers. High velocity at one vent and weak flow at another indicates duct imbalance, often from a collapsed flex run or a disconnected branch. The noise is your system telling you it’s fighting itself.
- Utility bills rising without rate increases. A 30% duct leakage rate can increase cooling costs by 20-30% in San Antonio’s climate. If your summer bills climbed $80-$150 year-over-year and your usage patterns haven’t changed, the ductwork is the first place to inspect.
- Musty or chemical odors when the system runs. Leaky return ducts pull air from wherever they can, including garages, attics with rodent activity, or wall cavities where previous owners stored pesticides. The smell is diagnostic; it tells us where to pressurize-test first.
BeforeAfterOur Duct Repair & Sealing Process - Step by Step
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Systematic inspection with photo documentation. We remove every register and insert a camera on a flexible borescope, photographing the inside of each duct run from the boot to the main trunk. You see what we see: collapsed flex, separated seams, debris accumulation, or corrosion. This is Haven Standard Clause 2: Documented Condition. No guesswork, no sales pressure based on what “might” be there.
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Pressure testing and leak quantification. We temporarily seal all registers and pressurize the duct system to 25 Pascals, measuring total leakage with a calibrated manometer. San Antonio homes average 15-25% leakage; we show you the number, compare it to the 12% maximum recommended by the National Comfort Institute, and explain what that percentage costs you in real dollars on your CPS Energy bill.
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Written scope and price before any work begins. Based on the inspection and pressure test, we deliver a written proposal with line-item pricing for each repair category: sealing, replacement, insulation, or metal repair. Haven Standard Clause 1: Written Price Before Work Starts. You approve the scope or modify it before a single panel comes off. “Call for a quote” does not exist in our process.
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Execution with trade-specific techniques. Our technicians, background-checked and uniformed under Haven Standard Clause 3: Verified Crews, execute the approved scope using Rotobrush and Nikro equipment for access and debris removal, Guardsman mastic for sealing, and Abatement Technologies HEPA containment where fiberglass disturbance requires it. Every repair is photographed at completion.
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Post-repair verification and deliverables. We re-pressurize the system and show you the improved leakage number. You receive a complete job record: before-and-after photos of every duct run, the pressure test results, the written scope you approved, and the 365-Day Done Right Promise in writing. If the work is not right, we make it right. This is not subject to manager approval. It’s a written guarantee on every job.
How Much Does Duct Repair & Sealing Cost in San Antonio?
Duct sealing for a typical 2,000-2,800 square foot home in San Antonio runs $280-$650 when accessible from the attic or crawl space and limited to mastic application at seams and joints. Flex duct replacement, which becomes necessary when sections are collapsed, crushed, or degraded by attic heat, ranges $180-$340 per run depending on length and R-value. Metal duct repair, more labor-intensive due to fitting and fabrication, typically falls between $320-$780 per section. Full duct insulation wrapping for an existing system averages $1,200-$1,850 for a complete attic installation.
Several factors move these numbers. Attic accessibility is the largest: truss construction with 18-inch clearance in Terrell Hills is straightforward; 6-inch clearance over a cathedral ceiling in Alamo Heights requires additional time and temporary decking. The extent of damage matters too. A single collapsed flex elbow in Live Oak is a 90-minute repair; a 1990s system in Kirby with original unsealed metal trunk and degraded flex branches is a full-day project. Material grade affects longevity: R-8 flex duct costs more than R-6 but delivers measurable efficiency gains in San Antonio’s climate.
To avoid overpaying, get the scope in writing before work starts, and verify that “sealing” means mastic at every seam, not a quick tape application at visible joints. Ask for a pressure test number before and after; without measurement, you’re buying a promise, not a result. CleanRun provides this documentation on every job. Bring a competitor’s written estimate and we’ll deliver a free second opinion with our number next to theirs, no obligation. Call (726) 600-7155.
Duct Repair & Sealing Near San Antonio - Our Service Area
CleanRun serves homeowners across Bexar County and adjacent communities, with crews regularly dispatched to Duct Repair & Sealing in Alamo Heights, Duct Repair & Sealing in Castle Hills, Terrell Hills, Leon Valley, Kirby, Windcrest, Helotes, Live Oak, Converse, Universal City, and Selma. Most locations within Loop 1604 see same-week scheduling; outer areas like Helotes and Selma typically book within 5-7 business days. Every appointment is confirmed by name: you’ll know your technician’s name before they arrive, and they’ll arrive in a marked CleanRun vehicle with license verification available on request. For our full service overview, visit our home page.
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.
Frequently Asked Questions - Duct Repair & Sealing in San Antonio
Duct repair and sealing fixes the physical integrity of your ductwork, closing leaks, replacing damaged sections, and restoring proper airflow; duct cleaning removes accumulated debris from intact ducts. You can have perfectly clean ducts that still leak 30% of your conditioned air into the attic, or sealed ducts that still need debris removal. We often perform both services on the same visit, but they address different problems. Call (726) 600-7155 and we’ll inspect to determine what your system actually needs.
Most residential duct sealing jobs in San Antonio take 3-5 hours; flex duct replacement adds 1-2 hours per run; full metal duct repair or insulation wrapping can extend to a full day. We give you a time estimate in writing with the price, before work begins, so you can plan your day. The 365-Day Done Right Promise covers our workmanship regardless of job duration.
A typical duct sealing job for a standard San Antonio home runs $280-$650; flex duct replacement is $180-$340 per run; metal repair ranges $320-$780 per section; full insulation wrapping averages $1,200-$1,850. The exact price depends on attic accessibility, damage extent, and material grade, which is why we inspect and deliver a written price before any work starts. Estimates are free. Call (726) 600-7155.
Yes. We repair ductwork connected to all major HVAC brands, including systems with Honeywell and Aprilaire air cleaners, media filters, and zoning controls. Our equipment roster includes Rotobrush and Nikro for duct access and debris management, and we stock common fittings and transition pieces for seamless integration. Whether your system is a 2023 variable-speed install in Universal City or a 2008 builder-grade unit in Converse, we can assess and repair the ductwork. Bring any written estimate for a free second opinion.
We do not market emergency dispatch for duct repair because duct leakage, while costly, is not typically an immediate safety hazard. However, our phones are answered by a live person 24/7, and we maintain a standby list for same-day response when a system failure has caused complete loss of cooling during San Antonio’s summer heat events. If you’re without cooling and suspect a collapsed or disconnected duct is the cause, call (726) 600-7155 and we’ll triage your situation directly.
Every duct repair and sealing job is backed by the 365-Day Done Right Promise: if the work is not right, we make it right, in writing, not as a policy subject to manager approval. This covers mastic adhesion, flex duct support integrity, and metal fabrication seams. The promise is delivered as a written document with your job record, alongside your before-and-after photo documentation. Haven Standard Clause 4: Accountable Results.
Clear a path to your attic access, HVAC closet, and all registers; secure pets in a separate room; and have your most recent CPS Energy bill available if you’d like us to estimate your leakage cost in dollars. You don’t need to move furniture unless it blocks a register. We’ll photograph everything before we touch it, and we’ll show you the photos before we leave. Call (726) 600-7155 to schedule.
Schedule Your Duct Repair & Sealing Service in San Antonio Today
Call CleanRun Air Duct Cleaning San Antonio at (726) 600-7155 for a free estimate with a written price delivered before any work starts. Every job includes a documented photo record of every duct run, background-checked uniformed technicians identified by name before arrival, and the 365-Day Done Right Promise in writing. No per-vent pricing, no bait-and-switch, no urgency theater. Just documented evidence and a price you can hold us to.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving San Antonio since 2013.