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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After
Before
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Before
AfterFast, Reliable Duct Sealing Across Boulder
Duct sealing in Boulder typically runs $800 – $2,400 for whole-home systems, with most single-family homes falling in the $1,200 – $1,800 range. We dispatch crews from our Denver office and schedule Boulder jobs with arrival windows that respect your time, not vague “sometime between 8 and 5” promises. Our technicians know the difference between a 1960s ranch off Baseline Road with original galvanized ducts and a newer build in North Boulder with flex-duct runs that need a different approach entirely. Call (361) 326-5060 for a written estimate before any work starts.
Boulder’s combination of older housing stock, wildfire smoke infiltration, and dual duct systems from swamp coolers creates sealing challenges you won’t find in many other Front Range cities. We’ve worked in homes from Mapleton Hill to Table Mesa where the same leak pattern shows up again and again: cooler ducts pulling attic air through gaps that heating-only systems never develop. That local pattern recognition matters when we’re tracing airflow problems.
Why Hollis Air Duct Cleaning Is Boulder’s Preferred Duct Sealing Company
We’ve been part of the Garrison Partners family since 2004, and our crews have sealed ducts in Boulder long enough to know which neighborhoods built in the 1950s and 1960s are still running original metal ductwork. In Martin Acres, we regularly find galvanized supply lines with corroded seams that leak 20 – 30% of conditioned air into crawl spaces. In Newlands, the story’s often flex duct from a 1980s renovation that’s sagging and pulling apart at the collars. That specificity shows up in how we quote the job and what materials we load on the truck.
Our Boulder customers come back because we price in writing before touching anything, and because our 365-Day Done Right Promise means if a seal fails or a leak reopens within a year, we return and fix it at no charge. No renegotiation, no “that wasn’t covered.” Background-checked, uniformed technicians arrive inside the quoted window, work under The Garrison Standard, and leave the site clean. Phones are answered by a live person 24 hours a day, seven days a week, so you’re not waiting until Monday to schedule.
Duct Sealing Services in Boulder
Duct Sealing Services in Boulder address the specific leak patterns that develop in this city’s older housing stock and its unique dual-duct configurations. The job involves pressurizing your duct system to locate leaks, then sealing them with mastic compound or metal-backed tape rated for HVAC use, never the gray cloth tape that dries and fails within a season. Most Boulder homeowners need sealing when rooms won’t hold temperature, energy bills spike without explanation, or a duct blaster test shows leakage above 10% of total airflow. A typical whole-home duct sealing job in Boulder runs $1,200 – $1,800, with larger homes or systems requiring extensive access work reaching the upper end.
Leak Detection and Airflow Testing
We start every sealing job with a pressure test using calibrated equipment that measures exactly how much air your ducts are losing and where. In Boulder’s hillside homes near Chautauqua, we often find return leaks pulling in crawl-space air laced with radon, while supply leaks in older ranches off Arapahoe pressurize attics and drive moisture into insulation. The test gives us a baseline and lets us show you the before numbers in writing.
Mastic Sealing and Joint Reinforcement
Where we find gaps at seams, collars, or register boots, we apply duct sealing mastic, a thick, fiber-reinforced compound that remains flexible as metal expands and contracts through Boulder’s temperature swings. For larger gaps or deteriorated connections, we add metal-backed tape beneath the mastic for mechanical reinforcement. This matters in Boulder particularly because our semi-arid climate creates wide daily temperature ranges that stress duct materials more than in milder zones.
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.
Duct Insulation in Boulder
Duct Insulation in Boulder solves a problem that many homeowners don’t realize they have: conditioned air bleeding thermal energy through thin metal or uninsulated flex duct before it ever reaches your rooms. In Boulder’s climate, where summer days hit the 90s and winter nights drop below 20, uninsulated attic ducts can lose 15 – 25% of heating or cooling capacity to the surrounding space. We typically see this in older Boulder homes with original galvanized supply lines and in any home where flex duct was added without wrapping. Duct insulation runs $600 – $1,500 in Boulder depending on linear footage and attic accessibility, with most jobs landing at $900 – $1,200.
Attic Duct Wrapping and Encapsulation
Our crews wrap accessible duct runs with formaldehyde-free fiberglass insulation jacketed with a reinforced vapor barrier, then seal the seams with matching tape. In Boulder’s dry climate, vapor drive is less aggressive than on the Gulf Coast, but temperature swings still create condensation on cool supply lines in humid summer periods when monsoonal moisture moves through. Proper wrapping prevents that condensation from saturating surrounding insulation.
Crawl Space and Basement Runs
Homes in Boulder’s older neighborhoods like Whittier and Goss-Grove often have ductwork in dirt-floored crawl spaces that never got insulated during original construction. We insulate these runs with products from Air Duct Cleaning in Boulder that resist mold growth, important because those same crawl spaces often harbor moisture from irrigation runoff against foundation walls.
Trusted Brands We Service in Boulder
Our trucks carry professional-grade equipment and materials from Nikro, Honeywell, Aprilaire, and Abatement Technologies, the same brands commercial HVAC contractors specify for hospitals and schools. For Boulder homeowners, that means we don’t need to special-order basic materials or make return trips because the truck lacked the right tape or mastic for your system. We stock Nikro negative-air accessories for jobs where sealing requires temporary containment, Honeywell filtration components for homes upgrading their air cleaning alongside duct repairs, and Aprilaire humidity control products that pair well with sealed duct systems in Boulder’s variable climate. Parts availability keeps our turnaround tight and your job moving.
Common Duct Sealing Problems We See in Boulder Homes
- Swamp cooler duct separation: Many Boulder homes run separate duct systems for evaporative cooling and forced-air heating. The cooler ducts, often lightweight flex or fiberboard, develop gaps at seams where constant moisture exposure weakens connections. We seal these with compounds rated for wet environments, then recommend Dryer Vent Cleaning in Boulder to complete your system’s airflow maintenance.
- Wildfire smoke infiltration through return leaks: During Front Range fire seasons, negative pressure from return duct leaks pulls smoky attic air directly into your living space. We’ve traced this in homes near the foothills where the smoke smell persisted even with windows closed, and sealing the return system stopped it.
- Corroded galvanized seams in mid-century homes: Original ductwork from the 1950s through 1970s in neighborhoods like South Boulder and Table Mesa often shows seam corrosion where decades of condensation collected in low spots. Mastic sealing extends service life, though we flag sections where replacement makes more sense than repair.
- Flex duct sagging and collar separation: 1980s and 1990s renovations frequently used flex duct routed through hot attics, and Boulder’s intense summer sun degrades the outer jacket. Sagging creates low points where debris collects and collars pull away from boots, leaking conditioned air into unused spaces.
Pricing for Duct Sealing in Boulder, CO
Whole-home duct sealing in Boulder typically costs $800 – $2,400, with most single-family homes in the $1,200 – $1,800 range. Smaller condos or townhomes with simple basement duct runs may fall toward the lower end; larger homes with multiple zones, extensive attic work, or access through finished spaces trend higher. What moves the number: linear footage of ductwork, accessibility (crawl space vs. open basement), whether we’re sealing one system or both heating and cooling ducts, and whether insulation removal or replacement is needed to reach the leaks.
We give you one flat price per system, agreed in writing before any work starts. No per-linear-foot add-ons, no “we found more leaks” surprises when the technician is already in your home. The price covers pressurized testing, all sealing materials, and cleanup. If you want a duct blaster verification test after sealing to document improvement, we include that. Call (361) 326-5060 for a free estimate with exact numbers for your home.
We Also Serve Cities Near Boulder
Our Duct Sealing in Boulder crews travel throughout the Front Range, including Duct Sealing work in Denver, Greeley, Fort Collins, and Colorado Springs. Each job carries the same written pricing, the same 365-Day Done Right Promise, and the same live-answer scheduling whether you’re in central Boulder or forty miles down I-25.
Serving Boulder, CO - Our Local Coverage Area
We’re based in the Boulder 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 Boulder
We typically schedule Boulder appointments within 3 – 5 business days, with dispatch coordinated from our Denver office to keep arrival windows tight. Call (361) 326-5060 to check current availability for your neighborhood.
Yes, we seal ducts throughout Boulder, from downtown and the University Hill area to Pine Brook Hills and the mountain neighborhoods west of town. Foothills homes often need extra attention to return duct integrity because of longer duct runs and greater pressure differentials.
Boulder pricing runs roughly comparable to Denver, sometimes 10 – 15% higher for homes with complex access or dual duct systems from swamp coolers. The $1,200 – $1,800 typical range holds across both markets; your specific home’s layout matters more than the zip code.
Every duct sealing job is covered by our 365-Day Done Right Promise: if any seal fails, any leak reopens, or airflow problems return within a full year, we come back and make it right at no charge, including a free second visit. This is backed in writing on every invoice, not a verbal “satisfaction guarantee.”
We pressure-test before and after, show you the numbers, and can run a duct blaster verification if you want third-party documentation. Many Boulder homeowners also notice the difference in room-to-room temperature balance and lower utility bills within the first billing cycle. Call (361) 326-5060 to schedule your free estimate.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Boulder since 2004.