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 Sealing Nationwide
Duct sealing typically costs $800 – $2,400 for a whole-home system depending on access, duct material, and leak severity. Most residential jobs are completed in a single day, and Hollis Air Duct Cleaning provides a written price before any work begins. Call (361) 326-5060 for a free estimate.
We’ve been sealing ductwork since 2004 as part of the Garrison Partners family. Our crews use professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies to find and fix leaks that waste energy and let conditioned air escape into attics, crawl spaces, and wall cavities. Every technician is background-checked and uniformed, and every job carries our 365-Day Done Right Promise in writing.
Leaky ducts force your HVAC system to run longer, which drives up utility bills and shortens equipment life. The Department of Energy estimates the average home loses 20 – 30% of conditioned air through duct leaks. We seal with mastic compound and metal-backed tape, not the hardware-store duct tape that dries out and fails within a year. The price we write down is the price you pay. No per-vent add-ons, no surprises when the van is in your driveway.
Duct Insulation
Duct Insulation wraps your sealed ductwork in thermal barrier material to keep heated or cooled air at temperature as it travels through unconditioned spaces. You need it when ducts run through attics, garages, or crawl spaces where extreme temperatures steal energy before air reaches your rooms. Hollis Air Duct Cleaning installs fiberglass wrap and rigid foam insulation after sealing is complete, with whole-home insulation projects typically running $1,200 – $3,500 depending on linear footage and R-value required. We use Guardsman and Honeywell filtration-compatible materials that meet current energy code standards.
When Insulation Matters Most
Homes built before 1990 often have uninsulated metal ductwork in attics that reach 140°F in summer. Without insulation, your 55°F conditioned air warms to 75°F before it exits the vent. We measure supply-air temperature drop at each register to pinpoint where insulation will pay for itself fastest.
Insulation After Sealing
Insulating leaky ducts is like pouring water into a cracked bucket. Hollis seals first with mastic, then insulates, so you’re not trapping moisture inside the wrap where it breeds mold. Our written scope specifies both steps separately, with prices for each, so you know exactly what you’re buying.
HVAC Duct Sealing
HVAC Duct Sealing is the process of closing gaps, seams, and disconnected joints in the metal or flexible ductwork that connects your furnace and air conditioner to every room. You need it when rooms never reach set temperature, when utility bills spike without explanation, or when a duct blast test shows leakage above 10% of total airflow. Hollis Air Duct Cleaning performs pre- and post-sealing pressure tests using calibrated fan equipment, with residential HVAC duct sealing ranging from $800 – $2,400 for most homes. We document the before-and-after leakage rate in writing.
Pressure Testing First
We don’t guess where your leaks are. Our crews use a duct blaster fan and manometer to pressurize the system and measure total leakage in CFM25, cubic feet per minute at 25 Pascals. This number tells us whether sealing will solve your problem or if duct redesign is the smarter fix.
Mastic vs. Tape
We brush on water-based duct mastic at every seam and joint, then reinforce with metal-backed tape where code requires it. Mastic remains flexible for decades; foil tape cracks in 3 – 5 years. Our 365-Day Done Right Promise covers both materials and labor if any seal fails within the first year.
Duct Repair
Duct Repair fixes physical damage to your ductwork including crushed flexible ducts, corroded metal sections, and disconnected trunk lines that leak air or draw in attic dust and insulation fibers. You need it after pest damage, remodeling accidents, or when visible ductwork shows rust holes, kinks, or sagging. Hollis Air Duct Cleaning replaces damaged sections with matching material, reconnects trunk-to-branch joints with mechanical fasteners and mastic, and repairs typically run $400 – $1,800 depending on accessibility and extent of damage. Every repair is covered by our 365-Day Done Right Promise.
Crushed Flex Duct Replacement
Flexible ductwork gets flattened by storage boxes, compressed by workers in attics, or chewed by rodents. A fully crushed 8-inch flex duct drops airflow by 50% or more. We replace with new insulated flex of matching diameter, supported every 4 feet to prevent sagging, and seal both ends with draw bands plus mastic.
Metal Duct Corrosion
Galvanized steel ducts rust from the inside out when condensation forms without proper insulation. We cut out corroded sections, fabricate replacement pipe or fittings, and seal with mastic and sheet-metal screws. For extensive corrosion, we’ll show you the damage with a borescope camera before quoting replacement.
Air Duct Sealing
Air Duct Sealing targets the supply and return ductwork that moves conditioned air throughout your home, closing leaks that waste energy and compromise indoor air quality. Many homeowners wonder about DIY vs Professional Duct Sealing: What’s Safe to Do Yourself. You need it when you notice hot or cold spots, excessive dust, or musty odors that suggest attic air is being pulled into the system. Hollis Air Duct Cleaning seals from both the inside using aerosolized sealant technology and from the outside at accessible joints, with whole-home air duct sealing priced from $800 – $2,400. We provide before-and-after photos of your actual ductwork.
Aerosol Internal Sealing
For systems with limited attic access, we offer aerosol duct sealing that pressurizes the ductwork and atomizes vinyl polymer sealant particles. Leaks act as exits, particles stick at leak edges, and seals build to 1 – 2 millimeters thick. This method reaches leaks inside walls that hand-sealing cannot touch, typically reducing leakage by 80 – 90%.
Accessible Joint Sealing
Where ducts are reachable, we brush mastic onto every longitudinal seam, transverse joint, and takeoff connection. We remove old, dried tape first because sealing over it guarantees failure. Our crews carry extension poles and headlamps to reach deep trunk lines without compressing insulation.
Duct Sealing Services
Duct Sealing Services from Hollis Air Duct Cleaning cover inspection, testing, sealing, and documentation for residential and light commercial HVAC systems. You need these services when energy bills trend upward, when rooms stay uncomfortable despite thermostat settings, or when an energy audit flags duct leakage. Our standard duct sealing service includes pressure testing, manual sealing of accessible leaks, aerosol treatment where appropriate, and a written report with before-and-after leakage rates, with pricing from $800 – $2,400 for typical homes. We schedule appointments by phone, answered live 24 hours a day.
What’s Included in Every Service
Every duct sealing service starts with a visual inspection and duct blaster test, continues with sealing using mastic and/or aerosol methods, and ends with a post-test to prove results. You receive written documentation of leakage reduction, photos of sealed areas, and our 365-Day Done Right Promise. If any seal fails within a year, we return at no charge.
Commercial System Services
Light commercial buildings with rooftop units and exposed ductwork face the same leakage problems as homes, often worse due to longer duct runs. We seal commercial systems up to 5 tons capacity using the same mastic and tape methods, with pricing scaled to linear footage and access difficulty. Call (361) 326-5060 for a commercial estimate.
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.
Brands We Service
We’ve serviced and sealed ductwork connected to Carrier, Trane, Lennox, Rheem, Goodman, York, Bryant, American Standard, Ruud, and Amana systems, plus hundreds of others. Our crews carry fittings and adapters that mate with proprietary plenum connections from each manufacturer. We’ve sealed ducts on Rotobrush rotary brush cleaning systems and verified seal integrity with Nikro negative-air machines on the same day.
Whether your HVAC is a 2-ton Rheem in a 1950s ranch or a 5-ton Carrier in a new build, we understand how that brand’s airflow specs affect sealing strategy. We stock mastic, tape, and replacement duct sections sized for each system’s static pressure requirements. Whether you have Honeywell, Aprilaire, or any other make of air cleaner or filtration equipment attached to your ducts, we can help.
Signs You Need a Pro Right Now
- Rooms that never match the thermostat. If your bedroom runs 8°F different from the hallway despite the system running constantly, conditioned air is escaping before it arrives. Leaky supply ducts dump heated or cooled air into the attic; leaky returns pull attic air into the system.
- Dust that returns within days of cleaning. Excessive dust often means your return ducts pull air from attic spaces filled with insulation particles and rodent debris. Sealing returns stops this infiltration at the source, rather than trapping you in a cycle of cleaning and re-cleaning.
- Utility bills that jumped 20% or more with no rate change. When ducts leak 25% of conditioned air, your system runs 25% longer to achieve the same result. If your kWh or therm usage spiked and your utility rate stayed flat, duct leakage is the likely culprit.
- Musty or chemical odors from vents. Return leaks in attics or crawl spaces draw in off-gassing from insulation, pest droppings, or stored chemicals. These odors don’t respond to air fresheners because they’re being pulled in continuously while the fan runs.
- Visible gaps or disconnected ducts in attic or basement. If you can see daylight through a duct joint, or if a flex duct hangs disconnected from its collar, your system is pressurizing your attic instead of your bedrooms. This is energy waste you can literally see.
Our Process, Step by Step
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Schedule and confirm. Call (361) 326-5060 and a live person answers, 24 hours a day. We quote a 2-hour arrival window, send technician photos and bios before dispatch, and call 30 minutes out. No voicemail loops, no waiting until Monday.
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Inspect and test. Your technician walks the system with you, notes comfort complaints, then performs a duct blaster pressure test to establish baseline leakage in CFM25. We photograph accessible leaks and show you the test results on a digital manometer.
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Written price, your approval. We itemize sealing scope, materials, and labor in a written proposal. The price does not change once work begins. You approve in writing before we touch a tool. This is The Garrison Standard.
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Seal and verify. We seal accessible leaks with mastic and metal-backed tape, apply aerosol sealant where appropriate, then retest with the duct blaster to prove leakage reduction. We photograph sealed areas for your records.
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Document and guarantee. You receive written test results, photos, and our 365-Day Done Right Promise. If any seal fails within one year, Hollis returns and makes it right at no charge, including a free second visit if needed.
How Much Does Duct Sealing Cost?
A typical whole-home duct sealing project runs $800 – $2,400 depending on home size, duct accessibility, leak severity, and whether aerosol internal sealing is required. For nearby communities, we also offer Duct Sealing in Huntington Park. Small homes with accessible attics and minor leakage at joints may fall at the lower end. Larger homes with ducts buried in insulation, extensive corrosion, or the need for aerosol treatment to reach leaks inside walls trend toward the upper range.
Several factors move the price. Accessibility is the biggest: crews can seal exposed trunk lines in a walk-up attic in hours, while ducts buried under blown insulation require careful removal and replacement of that insulation. Duct material matters too; sealing metal ducts takes more labor per joint than sealing flex duct connections. The extent of leakage found during pressure testing determines material quantity and labor hours. Homes with 30% leakage need more work than homes with 12% leakage.
To avoid overpaying, get a written price based on a pressure test, not a per-vent estimate over the phone. Per-vent pricing encourages contractors to sell unnecessary work or skip hard-to-reach leaks. We test first, then quote a flat price for the whole system. Our free estimate includes the pressure test, visual inspection, and written proposal with no obligation. The estimate itself costs nothing, and we leave you with the test numbers whether you hire us or not.
What’s included: pre- and post-sealing pressure tests, all mastic and tape materials, aerosol treatment if specified, digital photos of sealed areas, written leakage reduction report, and our 365-Day Done Right Promise. What’s not included: duct repair or replacement (quoted separately if found during inspection), insulation removal and replacement (quoted separately), and HVAC mechanical repairs outside the duct system.
Where We Work
Hollis Air Duct Cleaning serves homeowners and businesses across the United States through a network of independently owned and operated locations, each held to The Garrison Standard. Every local crew arrives inside the quoted window, prices every job in writing before work starts, completes the work by the book, and leaves the site clean. You deal with a local business owner who answers for the work, backed by the systems and guarantees of the Garrison Partners family.
Frequently Asked Questions About Duct Sealing
Duct sealing closes gaps, seams, and holes in your HVAC ductwork to prevent conditioned air from escaping and unconditioned air from entering. We use brush-applied mastic compound, metal-backed tape at joints, and aerosol sealant technology for leaks inside walls. The goal is to deliver all the heated or cooled air your system produces to the rooms that need it.
Most residential duct sealing jobs are completed in 4 – 8 hours depending on home size and leak accessibility. Aerosol internal sealing adds 2 – 3 hours for setup and cure time. We schedule morning arrivals for jobs likely to run long, and we tell you the expected duration in writing before starting.
Whole-home duct sealing typically costs $800 – $2,400, with most homes falling between $1,000 – $1,800. The exact price depends on pressure test results, duct accessibility, and whether repair or aerosol treatment is needed. Call (361) 326-5060 for a free estimate with pressure test included.
Yes. We regularly seal ductwork connected to Honeywell whole-home air cleaners and Aprilaire humidifiers, dehumidifiers, and ventilation systems. Our crews understand how these accessories affect duct static pressure and sealing strategy, and we verify that seals hold under the airflow rates these systems require.
Phones are answered by a live person 24 hours a day, 7 days a week. We schedule urgent appointments for situations like disconnected trunk lines or major leaks causing extreme temperature swings, though most duct sealing is a planned maintenance service rather than an emergency repair.
Every duct sealing job carries our 365-Day Done Right Promise in writing. If any seal fails within one year, Hollis returns and makes it right at no charge, including a free second visit if the first repair needs adjustment. This is not a vague satisfaction guarantee; it’s a specific, dated, written commitment.
Clear a path to your HVAC unit, attic access, and all return and supply registers. Remove fragile items from work areas. We bring drop cloths and wear shoe covers, but access to every vent and the main plenum is essential for thorough sealing. We call 30 minutes before arrival so you can secure pets.
Schedule Your Duct Sealing Service Today
Call (361) 326-5060 now for a free duct sealing estimate. A live person answers 24 hours a day. We’ll schedule your pressure test, provide a written flat price before any work begins, and back every seal with our 365-Day Done Right Promise. No per-vent games, no price changes at the door, no voicemail loops. Get your estimate scheduled today.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving homeowners nationwide since 2004.