Fast, Reliable Duct Repair & Sealing Across Alamo Heights
Most duct repair calls we take from Alamo Heights are finished in one visit. Our crew knows the 78209 zip code well - from the mid-century ranches off Broadway to the older Tudors near the Alamo Quarry Market - and we stock the mastic sealant, flex duct, and metal fittings these retrofitted systems actually need on the truck. If your supply vents are blowing weak, your rooms won’t balance, or you’ve noticed a fine tan dust collecting around your registers every December through January, that’s likely unsealed ductwork pulling attic air into your living space. Call (866) 347-2063 and we’ll get someone out today or tomorrow.
Why Bellows Air Duct & Vent Co. of Texas Is Alamo Heights’s Preferred Duct Repair & Sealing Company
We’ve been driving to Alamo Heights since 1984. The homes here are different from newer San Antonio suburbs - they’re built-out, established, and their ductwork was retrofitted into wall cavities and attics never designed for it. That matters when you’re diagnosing why a system blows 55° air at the plenum but 72° air at the far bedroom vent.
Our Duct Repair & Sealing in Alamo Heights work is backed by the 90-Day Done Right Promise in writing. If the seal doesn’t hold, we return at no charge - no paperwork, no arguing. Calls are answered by a live person 24 hours a day, and our technicians are background-checked, uniformed, and equipped with camera inspection gear so you see the before and after yourself.
We’re not the cheapest outfit advertising a $59 whole-house special. We’re the ones you call when that cheap job failed two summers later and now your attic is 150°F and your ducts are leaking worse than before. One honest price shown before we start. The number on the phone is the number on the invoice.
Our Duct Repair & Sealing Services in Alamo Heights
Duct Sealing & Mastic Sealant Application
The retrofit duct systems common in Alamo Heights - metal trunks with flex duct stapled into unconditioned attics - fail at the transitions. We apply professional-grade mastic sealant at every metal-to-flex joint, every plenum connection, and every seam in the trunk line. Mastic outlasts foil tape by years, especially in San Antonio attics where summer temperatures exceed 150°F and thermal expansion cracks lesser materials within two to three seasons. Our crews carry high-temp mastic rated for these conditions, and we verify the seal with camera inspection before we leave.
Metal Duct Repair
Original galvanized duct runs from the 1950s and 1960s are still in service throughout Alamo Heights, particularly in the ranch-style homes north of Austin Highway. These metal trunks can be repaired if the shell is intact - we patch small corrosion spots, reinforce weak hangers, and re-seal joints that have worked loose from decades of thermal cycling. Where the metal has failed or been modified repeatedly by prior HVAC contractors, we splice in new sections and transition properly to existing flex runs. Every repair is pressure-checked and camera-verified.
Flex Duct Repair & Replacement
Flex duct stapled to old metal trunks in Alamo Heights attics degrades faster than in newer homes because the runs are longer, the attics are hotter, and the supports are often improvised. We replace collapsed or torn flex with properly sized, insulated duct, support it at correct intervals, and seal the connections with mastic rather than zip ties and hope. A proper flex repair in a 150°F attic should last 15 years, not three.
Air Leak Repair & Duct Insulation
Unsealed duct joints in Alamo Heights homes don’t just leak conditioned air - they pull in unconditioned attic air loaded with Hill Country pollen, humidity, and fiberglass particulate. We repair the leaks at their source, then insulate exposed metal and flex runs to prevent condensation and thermal loss. In homes with orphaned duct branches from multiple HVAC upgrades, we cap dead-end runs properly rather than leaving them to accumulate pollen strata and restrict airflow.
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 Alamo Heights
Our trucks carry equipment and materials from Rotobrush, Honeywell, and Aprilaire - the same brands serious HVAC contractors specify for retrofit work in older homes. We stock mastic sealant, flex duct, and metal fittings sized for the smaller chases and tighter clearances common in Alamo Heights’s mid-century construction. That means most jobs don’t wait on parts. We also source insulation and sealant rated for the extreme attic temperatures San Antonio summers produce, not the generic hardware-store grade that fails after one season in your ceiling.
Common Duct Repair & Sealing Problems We See in Alamo Heights Homes
- Unsealed metal-to-flex transitions pulling attic air into the supply stream. These retrofit connections were never properly sealed originally, and decades of thermal cycling have opened gaps that draw 150°F attic air - and everything in it - directly into your living space every time the blower runs.
- Thermal expansion destroying older mastic and tape seals within 2-3 years. San Antonio attics cook duct sealants. We remove failed tape and low-grade mastic, then re-seal with high-temp product rated for the actual conditions your system faces.
- Orphaned duct branches from multiple HVAC upgrades creating dead-end pollen traps. Homeowners in Alamo Heights’s 78209 zip code frequently find rooms that never cool properly because a prior contractor left a disconnected branch that now accumulates dense cedar-pollen strata and blocks airflow to active vents.
- Original 1960s galvanized duct with multiple seasonal pollen layers. We recently sealed a 1950s ranch-style home on Argyle Avenue where the metal duct joints in the attic were completely unsealed, causing a fine tan layer of Ashe juniper pollen to coat the interior of the supply trunks. Our crew applied mastic sealant at every transition and insulated the exposed flex runs to stop the infiltration.
Pricing for Duct Repair & Sealing in Alamo Heights, TX
A typical mastic sealant application for a 1,500-2,500 square foot Alamo Heights home runs $380-$650, depending on attic accessibility and the number of transitions. Flex duct repair or replacement of individual runs is usually $180-$340 per section. Metal duct repair, including patching, reinforcement, and proper re-sealing, ranges from $290-$580. Full duct insulation for exposed trunk lines in an unconditioned attic typically falls between $450-$890.
What moves the price: attic temperature and working conditions (150°F attics take longer and require proper scheduling), the number of orphaned branches we need to cap or reconnect, and whether prior repairs used incompatible materials we must remove first. We inspect with a camera before quoting, so you see exactly what we see. Every estimate is free, and our $50 Off Any Repair Over $250 standing offer applies to qualifying duct sealing work. Call (866) 347-2063 for your exact number - estimates are free, and we don’t start work until you approve the price in writing.
We Also Serve Cities Near Alamo Heights
Our Duct Repair & Sealing crews work daily in Terrell Hills, San Antonio, Windcrest, and Kirby - the same 78209-area service radius, same trucks stocked for retrofitted mid-century systems. If you’re in one of these neighboring communities and your home was built before 1970 with ductwork threaded through existing wall cavities, the same local expertise applies.
Serving Alamo Heights, TX - Our Local Coverage Area
We’re based in the Alamo Heights 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 - Duct Repair & Sealing in Alamo Heights
That tan, fibrous buildup is Ashe juniper - mountain cedar - pollen from the Hill Country, pulled into your supply stream through unsealed duct joints every December through January. In Alamo Heights’s retrofitted systems, the negative pressure draw of your blower sucks unconditioned attic air directly into the metal trunks, and the pollen settles in distinct seasonal layers. We see this characteristic buildup regularly in original 1950s-60s galvanized duct runs throughout the 78209 zip code. Sealing every transition with mastic stops the infiltration. Call (866) 347-2063 for a camera inspection - estimates are free.
Yes, and it must be. Those metal-to-flex transitions are the primary failure point in Alamo Heights’s retrofitted systems. We remove any failed tape or dried mastic, apply fresh high-temp mastic rated for 150°F attic conditions, and properly support the flex to prevent future separation. The stapled connections common in these homes were never designed to be airtight - we make them so. Call (866) 347-2063 and we’ll show you the before and after on camera.
A proper mastic sealant application using high-temp product should last 10-15 years, even in San Antonio’s extreme attic heat. However, if your system has mixed materials from multiple HVAC upgrades, or if prior repairs used tape or low-grade sealant, we recommend inspection every 3-5 years. The thermal expansion cycle in Alamo Heights attics is brutal on inferior materials. We back our sealing work with the 90-Day Done Right Promise, and we’ll note any systemic issues that might need earlier attention. Call (866) 347-2063 to schedule.
Sealing won’t stop pollen at your doors and windows, but it will stop your HVAC system from actively importing attic-loaded pollen through leaky ductwork. In Alamo Heights, where the Ashe juniper season is one of the most intense allergen events in the United States, a sealed duct system means your filtration actually has a chance to work - instead of the blower pulling unfiltered Hill Country air directly into your supply trunks. Many homeowners notice reduced dust accumulation and less respiratory irritation within the first season after proper sealing. Call (866) 347-2063 for a free estimate.
Most 1960s galvanized duct in Alamo Heights can be sealed and returned to service if the metal shell is structurally sound. We camera-inspect for corrosion holes, prior patchwork, and structural integrity. Where the trunk is intact, mastic sealing at joints and proper insulation of exposed runs often restores performance comparable to new duct at a fraction of the cost. Replacement becomes necessary only when corrosion is advanced or the duct has been modified beyond repair by repeated DIY or discount-contractor work. We’ll show you exactly what we find on camera before you decide. Call (866) 347-2063 - estimates are free, and we offer a Free Second Opinion on Any Written Estimate if you’ve already been told replacement is your only option.
Written by Wade Kellerman, Owner at Bellows Air Duct & Vent Co., serving Alamo Heights since 1984.