Duct Repair & Sealing Cost - Tested First, Written Price Second

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How Much Does Duct Repair & Sealing Cost in San Antonio?

Duct repair and sealing in San Antonio typically costs $285 to $1,400, with most homes landing between $450 and $900 depending on the number of leaks, accessibility of the ductwork, and whether you need spot repairs or whole-system sealing. Simple jobs like sealing a single visible leak at a supply boot can run as low as $150 to $250, while a full aeroseal-style treatment or extensive duct replacement in a large two-story home can push past $2,500.

At Cardinal Air Duct San Antonio, we give you a written price before any work starts, so the number you approve is the number you pay. Call (254) 347-3897 for a free estimate and we’ll walk you through exactly what your system needs.

Duct Repair & Sealing Cost Breakdown (2026)

Here is what homeowners in the San Antonio area can expect to pay for common duct repair and sealing work in 2026. These are real ranges based on jobs our team sees across Alamo Heights, Stone Oak, Helotes, and the broader Bexar County market.

These ranges hold true for most single-family homes across San Antonio, from older bungalows in Monte Vista to newer construction in Cibolo and Schertz. Townhomes and condos tend to come in on the lower end because there is less ductwork to begin with.

What most people actually pay

If you’re wondering what the “average” job looks like, it’s this: a homeowner notices one or two rooms that never cool properly, we send a technician out, they find four to six leaking joints and a poorly sealed supply plenum, and the total comes to $450 to $750. That’s the sweet spot. The fix usually takes one visit, three to five hours, and the difference in airflow is immediate.

What Affects Duct Repair & Sealing Pricing in San Antonio

• Age of the ductwork. San Antonio homes built before 1990 often have original metal ducts that have been patched, re-taped, and re-routed for decades. Older systems take longer to assess and may have hidden failures we only find with a pressure test.
• Accessibility. Attics in San Antonio are brutally hot from May through September. If ductwork runs through a low-clearance attic in a 1970s ranch in the Medical Center area, the labor cost is higher than a newer home in Alamo Ranch with a tall attic and easy access.
• Number of registers and returns. A 2,000 sq ft home with 12 supply vents and two returns has more connection points than a 1,200 sq ft home with 8 vents. Each boot connection is a potential leak point.
• Duct material. Flex duct is cheaper to replace per linear foot but degrades faster in San Antonio heat. Rigid sheet metal costs more upfront but lasts longer and seals more cleanly. We’ll give you a straight answer on which makes sense for your home, not just the cheaper option.
• Whether you need aeroseal or manual sealing. Aeroseal is a pressurized sealant system that seals leaks from inside the ducts. It runs higher, typically $1,500 to $2,500 for a full system, but it reaches leaks in inaccessible sections. Manual sealing costs less but only works where a technician can physically reach.
• Existing damage beyond leaks. If we find collapsed flex runs, rodent damage (common in older San Antonio neighborhoods near natural areas like Government Canyon), or mold in the ducts from humidity, the scope expands and so does the price.

Is Duct Repair Worth the Cost in San Antonio?

Short answer: yes, and the math isn’t close. The U.S. Department of Energy reports that typical duct systems lose 20-30% of conditioned air through leaks, gaps, and poor connections. In San Antonio, where summer temperatures routinely hit 100°F and air conditioning runs eight months a year, that’s real money leaking into your attic every single day.

Let’s put a number on it. If your monthly electric bill averages $220 during cooling season and 25% of your conditioned air is escaping through duct leaks, you’re paying about $55 a month to cool your attic. A one-time sealing job at $650 pays for itself in about a year. After that, it’s savings.

Beyond the utility savings, sealed ducts mean:

• Even temperatures. The bedroom that’s always 8 degrees warmer than the living room is usually a duct leakage problem, not an AC sizing problem.
• Less dust. Leaky return ducts pull in attic air full of insulation fibers and dust, then circulate it through your home.
• Longer AC life. When your system isn’t fighting duct leaks, it cycles less and lasts longer.
• Better indoor air quality. Leaks in return ducts can pull in contaminants from the attic, including rodent droppings and insulation particles.

Signs You Need Duct Repair or Sealing

We regularly walk into San Antonio homes where the homeowner called us for a routine duct cleaning, and we find leaks that explain exactly why their AC struggles. Here’s what to look for:

• Rooms that stay warm no matter what. The thermostat says 72°F, but the upstairs bedroom reads 79°F. That’s usually a supply duct leak or a disconnected run.
• Dust accumulates fast. If you dust on Sunday and by Thursday it’s back, leaky return ducts are often pulling attic air into your living space.
• Your electric bill spikes in summer. San Antonio CPS Energy customers know the pain of July and August bills. Duct leaks make those months worse than they need to be.
• You can feel air moving in the attic. If you go into the attic while the AC is running and feel air blowing where it shouldn’t, that’s conditioned air escaping.
• Duct lines look crushed or separated. A visual inspection reveals more than most homeowners expect. Flex ducts get pinched by stored items or start separating at the connectors over time.

If any of these sound familiar, call (254) 347-3897. We’ll do a proper inspection and show you exactly what’s going on, with photos, before recommending any work.

How to Save on Duct Repair & Sealing

Duct work is not a place to pinch pennies, but there are smart ways to keep the cost reasonable without cutting corners.

• Get a real inspection first. Some companies quote duct sealing without ever looking at your system. That’s a guess, not a quote. At Cardinal Air Duct San Antonio, we inspect first, then give you a written price. The estimate is free. Call (254) 347-3897.
• Bundle with duct cleaning. If your ducts need cleaning anyway, do both at once. We’re already in the attic, already have the equipment set up, and you’ll save on the combined visit. Our Duct Repair & Sealing in San Antonio service pairs naturally with a full system cleaning.
• Seal what’s accessible first. If your budget is tight, we can seal the leaks we can reach and monitor the rest. Even partial sealing cuts energy loss measurably.
• Don’t wait for total failure. A small leak is a small repair. A disconnected duct run that overheats your AC compressor for two San Antonio summers becomes a $4,000 replacement. Dealing with it early is always cheaper.
• Check for CPS Energy rebates. CPS Energy occasionally rolls out efficiency rebate programs for duct sealing and HVAC improvements. It’s worth a quick call to see what’s current this year.

Why Duct Leaks Happen in San Antonio Specifically

Every region has its own duct problems, and San Antonio’s climate creates a particular kind of stress on your system. Here’s what we know from doing this work in Bexar County for years:

• Extreme attic heat. Attic temperatures in San Antonio regularly exceed 140°F in summer. Flex duct outer jackets degrade under that constant heat, and tape adhesive dries out and fails. This is the #1 cause of duct leaks we see.
• Humidity swings. San Antonio alternates between humid spring and fall seasons and dry summer heat. Metal duct joints expand and contract, which loosens connections over time.
• Foundation movement. San Antonio sits on expansive clay soil, and many homes experience slab movement. When the house shifts, rigid duct connections at the plenum and boots can separate slightly. Those small separations add up.
• Rodent activity. Squirrels and rats are common in older neighborhoods with mature trees, like Olmos Park and Castle Hills. Rodents chew through flex duct in attics.
• DIY attic storage. Too many homeowners use the attic for storage and accidentally crush flex runs under boxes and holiday decorations. Crushed ducts restrict airflow and eventually split.

These are San Antonio specific problems with San Antonio specific solutions. A generic duct company that works in Minnesota doesn’t know how 140°F attic heat affects R-6 flex duct. We do.

How Duct Repair & Sealing Works

If you book with us, here’s exactly what happens, start to finish:

1. You call and a live person answers. Not a voicemail tree. Not a callback service. A real person, 24/7, ready to book your inspection or answer questions at (254) 347-3897.
2. We inspect and show you the problem. Our technician arrives in uniform. You know their name before they ring the doorbell. We walk through the attic, inspect the full duct run, take photos, and show you what we found on the spot.
3. You get a written price before work starts. Every Cardinal Air Duct San Antonio job includes a written price in advance. No change at the door. No surprise charges. That is the Relay Standard.
4. We do the work. We use mastic sealant, not cheap tape, at every accessible joint and boot. If aeroseal is the right solution for your home, we’ll tell you why. If flex runs need replacing, we quote that separately and clearly.
5. We verify the result. After sealing, we check airflow at the registers and confirm the leaks are sealed. You get before-and-after photo documentation as part of the job.
6. You pay from your phone. Digital invoice, payable by link. Done. The whole booking-to-invoice experience is built for your phone.

Every repair we make is backed by the 365-Day Done Right Promise. If the work isn’t right within 365 days, we return and correct it at no charge. That’s not a limited warranty on select parts. That’s a full year on every job we do. Led by Omar Haddad, our team has built the longest-standing satisfaction window in the trade.

Duct Repair vs. Duct Replacement: How to Decide

This is the question our technicians hear most often: should we patch and seal, or is it time to replace? Here’s the honest way to think about it.

When repair and sealing makes sense

• Ductwork is less than 15 years old
• Leaks are at accessible joints, boots, or the plenum
• The duct material itself is in decent shape (no mold, no collapse, no major rodent damage)
• Your total system airflow is acceptable in most rooms
• Budget is a factor and you want the highest ROI per dollar spent

Repair and sealing typically costs $150 to $1,000. Most San Antonio homeowners fall into this category.

When replacement makes more sense

• Ductwork is 20+ years old and showing its age
• Multiple flex runs are crushed, torn, or disconnected
• Mold is present inside the ducts (sealing won’t fix mold)
• Duplicate repairs have already been attempted and failed
• You’re replacing the AC system anyway and want clean, tight ductwork to match

Full duct replacement in San Antonio runs $1,800 to $7,000+ depending on home size. It’s a bigger investment, but if your ducts are at end-of-life, it’s the smarter long-term move. We’ll give you a straight recommendation either way, with the numbers to back it up.

Why Choose Cardinal Air Duct San Antonio

We’re part of the Relay Home Co. family, founded 2005. We operate on one principle: total visibility, from booking to invoice. Here’s what that means for you in practice:

• Written price before any work starts. Always. Not an estimate. Not a ballpark. A written price you approve before we touch anything.
• The Relay Standard booking experience. Live trackable arrival time. Before-and-after photo proof of the work. Digital invoice payable by link. All from your phone.
• Professional-grade equipment. We run Rotobrush brush systems for cleaning, Nikro HEPA vacuums for negative-pressure extraction (meaning loosened debris goes straight into the vacuum, not back into your living room), and Abatement Technologies containment units when needed. For filtration, we carry Honeywell, Aprilaire, and Guardsman products.
• Background-checked, uniformed technicians. You’ll know who is coming before they arrive, by name.
• A live person answers 24/7. No voicemail loops. No phone tag. No “we’ll get back to you next business day.”
• The 365-Day Done Right Promise. If the work isn’t right within a full year, we come back and make it right at no charge. Written guarantee on every repair, plus a free second visit if a repair fails.

Omar Haddad leads our San Antonio team, and he holds every job to the Relay Standard. No exceptions. No fine print.

FAQs – Duct Repair & Sealing Cost

How much does duct repair cost in San Antonio?

Duct repair in San Antonio typically costs $150 to $700 for spot repairs and sealing at accessible joints, boots, and plenum connections. Most single-visit repair jobs land between $285 and $500. Whole-system sealing runs higher, usually $900 to $2,500. Call (254) 347-3897 for an exact quote on your system; estimates are free.

Is it cheaper to repair or replace ductwork in San Antonio?

Repair is almost always cheaper in the short term: $150 to $1,000 for sealing and spot fixes versus $1,800 to $7,000+ for full replacement. The right call depends on duct age and condition. If your ducts are under 15 years old with localized leaks, repair is the smart money. If they’re over 20 years old with multiple failures, replacement usually wins long-term. We’ll give you a straight recommendation either way, with photos and a written price, before any work starts.

How much does aeroseal duct sealing cost in San Antonio?

Aeroseal duct sealing in San Antonio typically runs $1,500 to $2,500 for a whole-home treatment, depending on home size and leak severity. Manual mastic sealing at accessible joints runs $150 to $700. Aeroseal costs more because it seals leaks from the inside of the ducts, reaching sections a technician cannot physically access. For an exact quote on your home, call (254) 347-3897.

Can you repair ducts the same day?

In most cases, yes. If the leaks are localized and we can access them without specialized equipment, our technicians typically complete the job in one visit, three to five hours. Whole-system aeroseal treatments may require a second visit. When you call (254) 347-3897, we’ll tell you honestly whether same-day is realistic for your job.

How much does it cost to seal leaking ducts under a house?

In San Antonio, most homes have attic ductwork, not crawlspace or under-slab. For the few homes with crawlspace ducts, sealing typically runs $400 to $900 due to difficult access and the need for containment to keep insulation and debris out of the living space. Slab leaks in under-slab duct systems are a different issue entirely and usually require a specialized assessment. Call (254) 347-3897 and we’ll help you figure out what type of duct system your home has and what it will cost to repair.

Does homeowners insurance cover duct repair in San Antonio?

Sometimes, but only for covered perils. If a storm, fire, or sudden accidental event damages your ducts, your homeowners policy may cover the repair minus your deductible. Insurance generally does not cover leaks caused by normal aging, wear and tear, or poor original installation. If you’re filing a claim, we can provide documentation and photos to support your case.

Get Your Free Duct Repair Estimate

The fastest way to know what duct repair or sealing will cost in your San Antonio home is to have us look at it. Our estimate is free. Our written price arrives before any work starts. And if the work isn’t right within a year, we return and correct it at no charge under the 365-Day Done Right Promise.

Call (254) 347-3897 now and a live person will answer. We’ll book your inspection, give you a trackable arrival window, and have a named technician at your door. That’s what the Relay Standard means.

Back to home.

Pricing reflects the San Antonio market as of 2026. Cardinal Air Duct San Antonio offers free estimates – call (254) 347-3897.

Written by Omar Haddad, Owner at Cardinal Air Duct San Antonio, serving San Antonio and Bexar County since 2005.