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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AfterFast, Reliable Duct Sealing Across Ellicott City
Duct sealing in Ellicott City typically runs $450 – $1,200 for a whole-home system, and most jobs are completed in a single visit. We’re Hollis Air Duct Cleaning, part of the Garrison Partners family, and we’ve been sealing ducts in this market since 2004. Our crews know the difference between a standard suburban sealing job and the flood-recovery work that Ellicott City’s historic Main Street buildings demand after the Patapsco rises. Scheduling and dispatch are coordinated from our Washington, DC office, but the technicians who arrive at your door live and work in Howard County. Call (361) 326-5060 for a free written estimate.
Why Hollis Air Duct Cleaning Is Ellicott City’s Preferred Duct Sealing Company
We’ve earned our reputation in Ellicott City by treating every home like the unique structure it is, not applying a cookie-cutter seal-and-go routine. The Garrison Standard requires our techs to arrive inside the quoted window, price the job in writing before touching any equipment, and leave the site clean. That discipline matters here because Ellicott City’s housing stock is split between fragile 19th-century mill-era buildings and 1970s – 90s suburban systems, each with completely different failure modes.
Our technicians are background-checked and uniformed, and you’ll know who’s coming before they arrive. Every duct sealing job carries our 365-Day Done Right Promise in writing: if the seal fails or the leak returns within a year, we come back and make it right at no charge, including a free second visit. No negotiation, no runaround.
Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues, no waiting until Monday morning to schedule.
Air Duct Sealing in Ellicott City
Air Duct Sealing in Ellicott City means closing the gaps, disconnected joints, and crushed runs that let conditioned air escape into attics, crawl spaces, and wall cavities before it ever reaches your rooms. In a typical hillside colonial or split-level off Route 40 near Centennial Park, we find 20 – 30% air loss through leaks in the original sheet-metal trunk-and-branch system. In Main Street’s historic buildings, the problem is different: retrofitted ductwork installed decades after the stone walls went up, with joints that were never properly sealed to begin with. A whole-home sealing job in Ellicott City generally costs $450 – $1,200 depending on system size, accessibility, and whether we’re working around flood-damaged boots that need remediation first.
What the Job Actually Involves
We pressurize the duct system and use smoke pencils or digital manometers to pinpoint every leak, then seal joints and seams with mastic, a fiber-reinforced compound that stays flexible and won’t crack like tape. For buried runs in hillside homes, we access supply and return ducts hidden in chases and behind insulation, not just the visible connections in the basement.
When Sealing Becomes Remediation
If your home took on Patapsco River water during the 2016 or 2018 floods, standard sealing won’t stick until the silt and moisture are removed. We check for the horizontal sediment ring inside duct boots that tells us the system needs full decontamination before any sealant goes on.
Duct Sealing Services in Ellicott City
Duct Sealing Services in Ellicott City cover everything from spot repairs on disconnected branch runs to whole-system sealing for original 1980s sheet-metal installations. Our Duct Sealing team uses professional-grade equipment, including negative-air containment from Nikro and rotary brush systems from Rotobrush when duct cleaning must precede sealing. The price range holds at $450 – $1,200 for most residential systems, with smaller spot-sealing jobs sometimes running less. We don’t quote per-vent teaser prices that balloon once we’re inside your home. The written price you approve is the price you pay.
Spot Sealing vs. Whole-System Work
Spot sealing addresses specific failures: a crushed flex connection, a disconnected boot, a joint that’s opened from decades of thermal expansion. Whole-system sealing treats every joint, seam, and penetration in the duct network. Most Ellicott City hillside homes need whole-system work because the original 1970s – 90s installations were never fully sealed at the time of construction.
Flood-Recovery Sealing Protocol
For Main Street rowhouses and mill buildings, our Duct Sealing Services include camera inspection of retrofitted trunk lines and boot perimeters. If we find silt lines from the 2016 or 2018 floods, we clean before we seal. Mastic applied over damp, contaminated metal peels within a season. The Patapsco valley’s humidity makes that failure certain.
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 Ellicott City
We stock parts and sealing materials from Abatement Technologies, Guardsman, and Rotobrush, so most Ellicott City jobs don’t wait on shipped inventory. Our Nikro negative-air machines contain dust and debris during cleaning phases, and our mastic compounds are rated for the humidity swings that Patapsco valley homes experience. When filtration upgrades accompany sealing work, we source Honeywell and Aprilaire products. The equipment is professional-grade, not hardware-store gear, and we explain what each piece does while it’s running in your home.
Common Duct Sealing Problems We See in Ellicott City Homes
- Original retrofitted ductwork in Main Street mill-era buildings. These stone and brick structures were built for radiator heat, with ductwork added decades later. The branch runs are often undersized and disconnected at every joint. Sealing alone won’t fix the system if silt from the 2016 or 2018 floods is still caked inside the boot.
- Valley humidity destroying fresh sealant. Ellicott City’s low-lying homes stay damp longer than ridgeline properties after storms. Mastic applied without addressing moisture just peels and fails. We check humidity levels and dry the system before sealing.
- Hidden leaks in hillside sheet-metal systems. The 1970s – 90s trunk-and-branch ducts in split-levels and colonials off Route 40 and near Centennial Park have leaks buried behind insulation and inside wall chases. Techs who seal only visible basement joints miss the supply and return ducts that matter most.
- Flood-damaged boots with compromised perimeters. The horizontal silt line inside a duct boot tells our techs the system took on river water. The boot perimeter seal is shot, and the surrounding framing may be moisture-compromised. We seal only after remediation.
Pricing for Duct Sealing in Ellicott City, MD
A typical duct sealing job in Ellicott City runs $450 – $1,200 for a whole-home system. Spot repairs on specific leaks start around $200 – $350. What moves the price: system size (a 3,000-square-foot colonial has more ductwork than a 1,200-square-foot rowhouse), accessibility (crawl spaces and attic chases take longer), and whether flood remediation must precede sealing. We don’t do per-vent pricing. One flat price per system, agreed in writing before work starts. Every estimate is free, and every job carries the 365-Day Done Right Promise. Call (361) 326-5060 for your exact quote.
We Also Serve Cities Near Ellicott City
Our crews work throughout Howard County and into neighboring communities. We regularly seal ducts in Ellicott City, Columbia, Fulton, Savage, and Jessup. The same written pricing, same background-checked uniformed techs, same 365-Day Done Right Promise apply in every zip code we cover.
Serving Ellicott City, MD - Our Local Coverage Area
We’re based in the Ellicott City 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 About Duct Sealing in Ellicott City
Main Street’s 18th- and 19th-century buildings have retrofitted ductwork that was never properly sealed at installation, and the 2016 and 2018 floods introduced silt and moisture that compromise every joint. The combination of original poor sealing plus flood damage means these systems leak massively, short-cycle the air handler, and harbor mold. Call (361) 326-5060 for a free inspection.
We look for a horizontal sediment ring inside duct boots and floor registers, the telltale silt line left when floodwater receded. Our techs also run camera inspection through trunk lines to check for debris and moisture staining. If we find it, we clean and dry the system before any sealant goes on. Call (361) 326-5060 to schedule.
Sealing alone won’t stop mold if the ducts stay damp, but sealing combined with proper moisture control eliminates the stagnant, humid conditions that let mildew thrive. We address humidity before applying mastic, so the sealant lasts and the ducts stay dry. For a full assessment, call (361) 326-5060.
Original 1980s trunk-and-branch systems in these homes leak at every unsealed joint, especially where flex connections have degraded and where ducts disappear into wall chases behind insulation. We pressurize the system to find hidden leaks, then seal every accessible joint with mastic. Most of these jobs run $600 – $950. Call (361) 326-5060 for a written estimate.
No. Mill buildings need flood-recovery protocol: camera inspection, silt removal, moisture verification, then sealing. Centennial Park colonials typically need whole-system sealing of original sheet-metal with attention to buried runs. The equipment overlaps, but the sequence and priorities differ completely. We assess each home individually and price in writing before starting. Call (361) 326-5060.
Ready to stop losing conditioned air into your attic and walls? Call Hollis Air Duct Cleaning at (361) 326-5060 for a free written estimate on duct sealing in Ellicott City. We’ll arrive inside the quoted window, price the job before we touch it, and back every seal with our 365-Day Done Right Promise in writing.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Ellicott City and Howard County since 2004.