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.
Before
After
Before
After
Before
AfterFast, Reliable Duct Sealing Across Stamford
We dispatch our Duct Sealing crews to Stamford from our Hartford office, and most appointments book within a few business days. If you live in Springdale, Glenbrook, North Stamford, or down in Shippan, you’re inside our standard service zone. Call (361) 326-5060 and a live person will pick up, day or night.
Stamford’s housing stock is split in ways that matter for ductwork. You’ve got 1950s-60s ranches with galvanized steel ducts running through damp crawlspaces, 1980s contemporaries with flex duct in conditioned attics, and high-rise downtown units with entirely different systems. We don’t treat them the same. Our pricing is per system, written before we start, because a three-furnace North Stamford home and a single-system Springdale ranch are different jobs with different scopes.
We’ve been at this since 2004. Roy Castellanos leads our operation under The Garrison Standard: arrive inside the window, price in writing, work by the book, leave the site clean. Every job carries our 365-Day Done Right Promise in writing. If the seal fails within a year, we come back at no charge.
Why Hollis Air Duct Cleaning Is Stamford’s Preferred Duct Sealing Company
Stamford homeowners call us after they’ve dealt with the other kind of outfit: the coupon that tripled at the door, the crew that tracked mud through the hallway, the repair that failed again in six months. We’re the call they make second, and we aim to be the last.
Our technicians are background-checked and uniformed. You know who’s arriving before they knock. They carry professional-grade equipment: Rotobrush rotary systems, Nikro negative-air machines, and sealing products from Honeywell and Aprilaire. Not hardware-store tape and a prayer.
Phones are answered by a live person 24 hours a day. No voicemail loops. No “we’ll call you back Monday.” Scheduling runs from our Hartford office, but the crews serving Stamford live and work in Fairfield County. They know the difference between a crawlspace ranch off Hope Street and a waterfront system in Cove.
The 365-Day Done Right Promise is not a slogan. It’s written on every invoice. Work fails, we return free. That includes a free second visit. Most competitors won’t put that in writing.
Duct Repair in Stamford
Duct Repair in Stamford means fixing the physical damage that lets conditioned air escape into walls, attics, and crawlspaces. We see separated trunk joints in Springdale ranches, corroded galvanized runs in Shippan homes near the Sound, and crushed flex duct in North Stamford attics where a contractor stepped in the wrong place. A typical duct repair in Stamford runs $280 – $620 depending on accessibility and material.
When Repair Beats Replacement
A single separated joint or a corroded elbow doesn’t mean tearing out the whole system. We cut out the damaged section, fabricate a replacement from matching gauge metal, and seal it with mastic and mesh. The repair lasts if the surrounding duct is sound. We check that before we quote.
Crawlspace Access Issues
Many Stamford crawlspaces are tight, damp, and unlit. Our techs carry proper lighting, respirators, and encapsulation suits. If the repair requires extended work below grade, we’ll tell you before we start. No surprises once we’re under your floorboards.
Air Duct Sealing in Stamford
Air Duct Sealing in Stamford closes the gaps, cracks, and failed joints that leak heated or cooled air before it reaches your rooms. We use mastic, mesh reinforcement, and mechanical fasteners on metal systems, plus proper closure systems on flex duct. A typical whole-system sealing job in Stamford runs $1,200 – $2,400 for a single-furnace home, $2,800 – $4,500 for homes with two or three systems. Per-system pricing, agreed in writing.
The Springdale and Glenbrook Difference
Stamford’s postwar ranches in Springdale and Glenbrook often have a single furnace feeding long trunk runs through unheated crawlspaces, so a duct sealing job here is really a crawlspace-sealing job – the same duct leakage that barely matters in a conditioned North Stamford contemporary drives condensation and mold in these older, unconditioned runs. We seal the trunk joints, re-wrap insulation where freeze-thaw cycling has pulled it back, and verify static pressure at the air handler to confirm the seal held.
Pre-Sealing Cleaning Requirement
Sealing a dirty system traps debris behind the new seal with no way out. In North Stamford, oak and maple leaf litter plus pollen sit inside ducts. We negative-pressure clean with our Nikro system before we seal. Two separate operations, two separate line items, both written down upfront.
Trusted Brands We Service in Stamford
We stock parts and sealing materials from Honeywell, Aprilaire, and Abatement Technologies. Honeywell dampers and zone controls integrate with most Stamford zoning retrofits. Aprilaire media filters and sealing collars handle the pollen load from North Stamford’s dense canopy. Abatement Technologies HEPA containment protects finished spaces when we’re working in occupied homes. We don’t order parts from a catalog while your system sits open. Our trucks carry inventory for common Stamford configurations, and our Hartford warehouse stocks the oddball fittings for older galvanized systems still running in Glenbrook and Springdale.
Common Duct Sealing Problems We See in Stamford Homes
- Crawlspace trunk joints left unsealed. Sealing supply and return ducts in a conditioned space but leaving the crawlspace trunk joints unsealed – in Springdale and Glenbrook ranches that’s where the real leakage and condensation lives. We inspect the full run, not just the easy-to-reach sections.
- Failed tape in coastal humidity. Using tape or low-grade mastic on joints that see freeze-thaw cycling and coastal humidity in Shippan and Cove – the seal fails within a season and the corrosion keeps eating the galvanized metal underneath. We use mastic rated for the application, applied over mesh, with mechanical backup on stressed joints.
- Sealing over debris. Sealing a system that was never cleaned first – in North Stamford, oak and maple leaf litter plus pollen sit inside the ducts, and sealing over debris traps it behind the new seal with no negative pressure source removal to pull it out. Clean first, seal second.
- Insulation degradation from freeze-thaw. Stamford’s cold, damp winters near Long Island Sound cause duct insulation to pull away from joints, especially in unconditioned attics and crawlspaces. A proper sealing job includes re-securing or replacing degraded insulation, not just slapping mastic on the metal.
Pricing for Duct Sealing in Stamford, CT
Whole-system duct sealing in Stamford typically runs $1,200 – $2,400 for a single-furnace home, $2,800 – $4,500 for homes with two or three systems. Duct repair runs $280 – $620 per incident. These are honest ranges for Fairfield County, not teaser prices that balloon once the technician is inside.
What moves the number: number of systems, linear feet of duct, accessibility (crawlspace vs. conditioned attic), whether pre-sealing cleaning is needed, and if insulation replacement is required. We inspect, we measure, we write the price down. You approve it. Then we work. The price does not move at the door.
Every quote includes the 365-Day Done Right Promise in writing. If the seal fails, we return at no charge. Call (361) 326-5060 for a free estimate.
We Also Serve Cities Near Stamford
Our crews regularly work in Old Greenwich, Riverside, Cos Cob, and Greenwich. Same equipment, same pricing discipline, same written guarantee. If you’re near the Stamford line in one of these neighborhoods, we can typically schedule you on the same routing day.
Serving Stamford, CT - Our Local Coverage Area
We’re based in the Stamford 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 Stamford
Each system is priced and documented separately. A three-system North Stamford home typically runs $2,800 – $4,500 total, compared to $1,200 – $2,400 for a single-system ranch in Springdale. We seal each air handler and its duct network independently, verify static pressure per system, and provide separate before-and-after documentation for each. Call (361) 326-5060 and we’ll count your systems during the free estimate.
Yes, if the smell comes from condensation-driven mold growth on leaking joints. Sealing stops the warm, humid air from escaping into the cold crawlspace and condensing. But if mold is already established, sealing alone won’t remove it. We clean first, then seal, then verify. In Stamford’s damp crawlspaces, the sequence matters.
Coastal humidity and salt air accelerate corrosion of galvanized steel in Shippan and Cove. Trumbull is inland enough to avoid the salt load. We use corrosion-resistant mastic and proper insulation wrapping on coastal jobs, and we’ll tell you honestly if a section is too far gone to seal.
Most of the time, yes. We access ducts at the air handler, at existing registers, and through small access panels we can patch afterward. If your basement is fully finished with drywall over the trunk lines, we may need a strategic cut, but we minimize it and repair what we open. We’ll show you exactly where before we start.
You get a written invoice with the scope of work, static pressure readings before and after, photos of key joints and seals, and the 365-Day Done Right Promise in writing. For multi-system homes, documentation is per system. If we cleaned before sealing, you also get before-and-after photos from the camera inspection. No documentation, no proof the work happened. We don’t leave without it.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Stamford and Fairfield County since 2004.