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 Dundalk
Duct sealing in Dundalk typically runs $450 – $1,200 for a whole-home system, and most jobs are scheduled within a few days of your call. If your HVAC bills are climbing or rooms near St. Helena or Turner Station never reach the thermostat’s set point, leaky ducts are the likely culprit. We’re Hollis Air Duct Cleaning, part of the Garrison Partners family, and our Duct Sealing crew dispatches from our Baltimore office to serve Dundalk homeowners with the same written pricing and 365-Day Done Right Promise we’ve operated under since 2004. Call (361) 326-5060 for a free estimate.
Why Hollis Air Duct Cleaning Is Dundalk’s Preferred Duct Sealing Company
We’ve worked in Dundalk long enough to know the difference between a 1950s steelworker row house on Holabird Avenue and a 2023 townhome near Colgate Creek. That matters because the duct problems are completely different, and the fix has to match.
Our technicians are background-checked, uniformed, and held to The Garrison Code: arrive inside the quoted window, price in writing before touching anything, complete the job by the book, and leave the site clean. Every repair is backed by our 365-Day Done Right Promise. If the work fails within a year, we return and make it right at no charge, including a free second visit. The price you sign off on is the price you pay. No ballooning at the door.
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 for someone to pick up.
Duct Insulation in Dundalk
Duct Insulation in Dundalk addresses the heat loss and condensation that plague older duct runs, especially in the post-WWII homes near the old Bethlehem Steel mill where unconditioned attics and crawl spaces eat up HVAC efficiency. In Dundalk’s humid subtropical climate, cold air moving through poorly insulated ducts in a hot attic picks up moisture that drips onto ceilings and breeds mold. Proper insulation wraps the duct in a thermal barrier, keeping the air you paid to cool or heat at its intended temperature until it reaches the vent. A typical duct insulation job in Dundalk runs $600 – $1,400 depending on linear footage and accessibility.
When Attic Ducts Sweat
We see this often in Dundalk’s low-slope roof homes where ductwork runs through attic spaces that hit 120°F in July. Without insulation, the temperature differential between the 55°F supply air and the roasting attic creates condensation that stains drywall and degrades mastic seals. We use Abatement Technologies insulation wraps rated for Maryland’s humidity range, sealed at every joint.
Basement and Crawl Space Runs
Homes near Bear Creek or the Dundalk Marine Terminal often have ductwork in damp crawl spaces. Insulation here does double duty: thermal protection plus a vapor barrier that keeps groundwater humidity from corroding metal ducts. We inspect for existing damage before wrapping, because insulating over rust or mold traps the problem.
HVAC Duct Sealing in Dundalk
HVAC Duct Sealing in Dundalk closes the gaps, cracks, and disconnected joints that leak conditioned air into walls, attics, and crawl spaces before it ever reaches your rooms. In Dundalk’s older housing stock, we regularly find supply boots pulled away from drywall, plenum seams dripping mastic, and flex duct connections that have loosened from decades of vibration. Sealing with mastic and fiberglass mesh, or aerosolized sealant for inaccessible runs, restores system pressure and balances airflow between rooms. A typical HVAC duct sealing job in Dundalk costs $450 – $1,200 based on system size and access.
New Construction Debris Complications
Dundalk’s new-construction pockets on former industrial parcels hand over duct systems laced with drywall dust and framing debris that most builders never vacuum out before the first HVAC cycle. Sealing ducts without first removing this construction dust means mastic bonds to the dust film, not the duct wall. Joints peel open within a season. The debris keeps circulating. That’s why we treat duct sealing as a post-construction detail, not just a repair for aging homes. Brand-new homes here can need source removal before their first winter.
Shared Wall and Row House Challenges
In Dundalk’s tighter row-house neighborhoods, technicians often need to coordinate with neighbors to avoid cross-contamination during sealing work. Close setbacks and shared walls mean attic-side duct runs aren’t always accessible from the unit being serviced. We scope every run with a camera before quoting, so you’re not paying for work we can’t physically complete.
Trusted Brands We Service in Dundalk
Our vans stock parts and materials from Aprilaire, Abatement Technologies, Guardsman, and Rotobrush, the same professional-grade equipment commercial crews use. For Dundalk homeowners, that means no waiting on a parts order from Baltimore or beyond. If your system needs a specific boot seal, collar adapter, or filtration upgrade during a sealing job, we likely have it on the shelf. We also carry Honeywell and Aprilaire filtration products for homeowners who want to upgrade their air handling while we’re already in the system. Fast turnaround matters in Dundalk’s climate, where a day without proper airflow in August turns a house miserable fast.
Common Duct Sealing Problems We See in Dundalk Homes
- Construction dust sealing failures in new builds. We sealed a 2023-built townhome near Colgate Creek in Dundalk where the homeowner’s MERV 8 filter was loading up in under three weeks; our tech ran a camera inspection and found drywall dust and construction grit caked along the supply and return ducts, so we pulled negative pressure with a Rotobrush and HEPA filtration unit, agitated with Abatement Technologies tools, then sealed the leaky joints at the air handler and boot registers with mastic and mesh. Within a week her blower motor stopped short-cycling and the filter was holding normal life again.
- Undersized returns in 1940s-50s infill homes. Many Dundalk houses were built with return paths too small for modern HVAC loads. Sealing the ducts without addressing the return capacity creates a system that can’t move enough air, straining the blower and leaving rooms stale.
- Attic-side runs in low-slope row houses. Post-WWII homes near the old steel mill often have ductwork tucked under shallow roofs where technicians can’t reach without coordinated neighbor access. Partial sealing leaves the worst leaks untouched.
- Industrial grit accumulation near former mill sites. Ducts in neighborhoods downwind of the Bethlehem Steel legacy accumulate a distinct black, oily grit that standard cleaning misses and that interferes with sealant adhesion. We pre-clean with rotary brush agitation before applying mastic.
Pricing for Duct Sealing in Dundalk, MD
A typical duct sealing job in Dundalk runs $450 – $1,200 for a whole-home system. Duct insulation, when needed separately or in combination, adds $600 – $1,400. What moves the needle: linear footage of ductwork, accessibility (crawl space vs. open basement), whether we need to remove construction debris before sealing, and if the home has original galvanized duct that requires specialized collar fittings.
We give you one flat price per system, agreed in writing before any work starts. No per-vent pricing. No teaser coupon that balloons once the van is in your driveway. Every estimate includes a camera inspection so you see what we see. Call (361) 326-5060 for your free estimate.
We Also Serve Cities Near Dundalk
Our crews work throughout the Baltimore metro, including Duct Sealing in Dundalk and surrounding communities. If you’re in Essex, Rosedale, Middle River, or Baltimore city proper, the same written pricing, same equipment, and same 365-Day Done Right Promise apply. Scheduling is coordinated from our Baltimore office, with local technicians dispatched to your area.
Serving Dundalk, MD - Our Local Coverage Area
We’re based in the Dundalk 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 Dundalk
Most builders in Dundalk’s new-construction pockets never vacuum drywall dust and framing debris from ducts before the first HVAC cycle. That debris prevents proper sealant adhesion, so joints leak from day one, and the grit circulates through your home until it’s removed. We treat post-construction sealing as a standard detail, not an extra. Call (361) 326-5060 for an exact quote.
Yes, and sometimes more. Dundalk’s row houses have shared walls and tight setbacks, so leaked supply air pressurizes wall cavities and can push moisture and odors into neighboring units. The close construction also means your HVAC works harder to overcome the loss. We coordinate with adjacent homeowners when needed to seal properly.
We can, with caveats. Galvanized steel in Dundalk’s 1940s-50s homes often has rust at seams that sealing won’t fix, and early flex duct may be brittle or undersized. Our camera inspection identifies what’s salvageable. Where duct replacement makes more sense than sealing, we’ll tell you directly and quote both options in writing.
Hot or cold spots, high energy bills, and whistling registers point to leaks that need sealing. Sweating ducts, musty smells, and water stains near vents indicate condensation from missing or degraded insulation. Many Dundalk homes near the harbor need both. Our inspection determines which problem is primary. Call (361) 326-5060 to schedule.
The builder should have run a negative-pressure source removal on all ductwork after construction, then pressure-tested the sealed system to verify no leaks exceed 5% of total airflow. Most don’t. They should also have sealed all joints with mastic, not tape alone, and installed a proper filtration system rather than the cheapest fiberglass placeholder. We document what’s missing so you have a record.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Dundalk and the Baltimore metro since 2004.