Duct Sealing in Denver - Tested First, Written Price Second

Fast, Reliable Duct Sealing Across Denver

Duct sealing in Denver typically runs $450 – $1,200 for a whole-home seal, depending on system size and accessibility, and most jobs are scheduled within a few business days with a written price locked before any work begins. If you’re noticing uneven heating between rooms, dust pouring from vents in older neighborhoods, or utility bills climbing through Denver’s dry winters, sealed ducts are usually the fix. Call (361) 326-5060 for a free estimate, or read on to see how Denver’s specific climate and housing stock shape what we find in local homes.

Call (361) 326-5060

We’re based right here in Denver, with dispatch and scheduling run from our metro office. Our crews know the difference between a 1950s ranch in Glendale and a pre-war bungalow in Washington Park, and we carry the equipment to handle both. That local knowledge matters because Denver’s combination of one of the driest urban climates in the U.S. and some of the highest radon levels of any major metro area means duct work here is as much about sealing out dry-air dust infiltration and preventing radon distribution as it is about standard efficiency gains. It’s a dual focus you won’t find in most other cities, and it’s why we approach Duct Sealing with a different checklist in Denver than we would in a humid climate.

Why Hollis Air Duct Cleaning Is Denver’s Preferred Duct Sealing Company

We’ve been part of the Garrison Partners family since 2004, and our Denver operation runs on The Garrison Standard: arrive inside the quoted window, price in writing before touching anything, complete the job by the book, and leave the site clean. That standard was built for customers who’ve already dealt with no-shows, bait-and-switch pricing, or crews who vanished after the check cleared.

Our technicians are background-checked and uniformed, and you’ll know who’s arriving before they pull up. We use professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies, the same tools commercial crews rely on, and we explain what each piece does while it’s running in your home. Every repair is backed by our 365-Day Done Right Promise: if the seal fails within a year, we return and make it right at no charge, including a free second visit. The price is written down before work starts, and it does not move 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 to schedule.

Duct Insulation in Denver

Duct Insulation in Denver addresses a problem most homeowners don’t notice until winter: heated air bleeding into unconditioned attic or crawl spaces through thin, unwrapped ductwork. In a climate where January nights regularly drop below 20°F and furnace run times stretch for hours, uninsulated ducts can lose 20 – 30% of their thermal energy before the air ever reaches your vents. We typically see this in homes built before 1980, which describes the majority of Denver’s housing stock, especially the post-1950s tract homes in suburbs like Aurora and Lakewood where builders prioritized speed over efficiency.

A typical duct insulation job in Denver runs $600 – $1,500 for a full system, depending on linear footage and whether the ducts are accessible from an unfinished basement or require attic work. We use fiberglass wrap with vapor barrier rated for Colorado’s dry climate, sealed with mastic at every joint.

When Insulation Beats Sealing Alone

Some Denver homes have tight ducts that still bleed temperature. If your airflow is strong but rooms stay cold, insulation is the priority. We see this pattern often in ranch-style homes with long duct runs through unheated crawl spaces.

Attic Ducts in Older Neighborhoods

In Capitol Hill and Baker, where original galvanized steel ducts from the early 1900s run through unfinished attics, we combine insulation with sealing to address both thermal loss and the rust scale that flakes off into the air supply. The fix lasts longer when we handle both problems at once.

HVAC Duct Sealing in Denver

HVAC Duct Sealing in Denver targets the leaks, gaps, and disconnected joints that let conditioned air escape and pull unfiltered attic or crawl space air into your breathing supply. In Denver’s semi-arid climate, with only about 15 inches of annual precipitation and frequent winter inversions that trap pollutants, these leaks don’t bring moisture-driven mold like they would in Houston or Atlanta. Instead, they pull in fine dust, dry debris, and radon-laden soil gas, and the dry air increases static electricity that makes duct surfaces attract and hold more particulate matter. Sealing stops that infiltration at the source.

A typical HVAC duct sealing job in Denver costs $450 – $1,200 for a whole system, with smaller partial repairs starting around $250. We use mastic sealant and metal-backed tape rated for temperature cycling, not the hardware-store duct tape that dries and fails within a season. For larger systems or hard-to-access runs, we may apply aerosolized sealant that finds leaks we can’t reach by hand.

Pressure Testing Before and After

We run a duct blaster test to measure leakage in CFM at 25 Pascals, seal the system, then test again. Denver homeowners get the numbers in writing, so they know exactly what changed. Most pre-1980 homes we test in Denver leak 30 – 40% of their air; our target is under 10%.

Sealing for Radon Mitigation Support

Because Denver sits on uranium-rich geology with some of the nation’s highest radon levels, a tight duct system works with your radon mitigation fan rather than against it. We coordinate with mitigation contractors when both systems need attention, especially in homes near Cherry Creek and the foothills where soil gas pressure runs high.

Trusted Brands We Service in Denver

We stock parts and materials from Honeywell, Aprilaire, and Abatement Technologies for Denver customers, which means most repairs don’t wait on shipping. Honeywell media air cleaners and Aprilaire whole-house humidifiers integrate directly with sealed duct systems, and we size them for the airflow rates your newly tight ducts will actually deliver. For filtration upgrades tied to sealing work, we source Guardsman and Abatement Technologies HEPA products. Our Denver warehouse carries mastic, metal tape, and insulation wrap in the quantities needed for same-week scheduling on most jobs. If your system uses a specific brand component, we’ll match it rather than substitute.

Common Duct Sealing Problems We See in Denver Homes

• Original galvanized steel rusting in pre-war homes. In older Denver neighborhoods like Washington Park and Capitol Hill, ducts installed in the early 1900s develop interior rust and scale that flakes off into the air supply. Sealing alone won’t fix this; we assess whether the metal can be cleaned and sealed or if section replacement is the honest recommendation.
• Dry-climate tape failure at flex duct joints. Denver’s low humidity and wide temperature swings cause standard duct tape adhesives to dry and crack within a year. We remove the failed tape entirely and replace it with mastic and UL-181 rated metal-backed tape designed for Colorado’s conditions.
• Return air leaks pulling attic dust during inversions. When winter inversions trap pollutants over the Denver basin, leaky return ducts in unconditioned attics pull that stagnant air directly into your furnace stream. Homeowners notice more dust on surfaces and more frequent filter changes; the real fix is sealing the return path.
• Post-1950s tract homes with original fiberglass board ducts. Many Denver suburbs built during the 1950s – 1970s boom used fiberglass duct board that degrades at the seams. The material crumbles when handled, so we assess whether localized sealing is viable or if the homeowner needs a longer-term replacement plan.

Pricing for Duct Sealing in Denver, CO

We Also Serve Cities Near Denver

Our Denver-based crews travel throughout the Front Range, including Duct Sealing in Denver proper and surrounding communities: Boulder to the northwest, Greeley and Fort Collins to the north, and Colorado Springs to the south. Scheduling and dispatch are coordinated from our Denver office, so response times are fastest for metro-area homes. Call (361) 326-5060 to confirm coverage for your address.

FAQs About Duct Sealing in Denver