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 Greenwich
Duct sealing in Greenwich typically runs $800 – $2,400 per HVAC system depending on whether we’re working with flex duct in a downtown condo or century-old galvanized runs in a backcountry estate. Most Greenwich appointments are scheduled within a week, with our Hartford office coordinating dispatch to minimize wait times for homeowners in mid-country, backcountry, and along the shore from Old Greenwich to Byram. We’ve been driving these roads since 2004, and we know the difference between a 1920s stone-and-shingle estate with unlined plaster chases and a 2015 teardown with zoned flex duct. That matters because the sealing method, the materials, and the time on site change completely. Call (361) 326-5060 for a free estimate with a written price before any work starts.
Why Hollis Air Duct Cleaning Is Greenwich’s Preferred Duct Sealing Company
Greenwich homeowners don’t need another coupon in the mailbox. They need a crew that shows up uniformed, prices the job in writing, and stands behind it for a full year. That’s The Garrison Standard, and it’s how we’ve operated since 2004.
Our technicians are background-checked and arrive in marked vehicles. You know who’s walking into your home before they ring the bell. Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no “we’ll call you back Monday.”
The 365-Day Done Right Promise covers every duct sealing job in writing. If the seal fails or the leakage returns within a year, we come back at no charge. That includes a free second visit, not a negotiation.
We’re familiar with the specific headaches Greenwich properties present: damp stone-wall chases in backcountry estates, flex-duct sag in downtown condos, and the seasonal condensation cycles that stress both. Our Duct Sealing in Greenwich crews carry mastic rated for high-humidity environments and foil tape that holds through Connecticut freeze-thaw.
HVAC Duct Sealing in Greenwich
HVAC Duct Sealing in Greenwich means stopping conditioned air from leaking into attics, crawlspaces, and wall cavities before your furnace or air handler wastes energy heating or cooling spaces you don’t live in. In this market, the job varies sharply by neighborhood. A backcountry estate off Round Hill Road may have 1930s galvanized trunk lines running through unheated attic space, while a Byram condo built in 2015 likely has flex duct that needs re-strapping and register-boot sealing instead of chase encapsulation. We price per system, not per vent, and we write that price down before touching anything.
Typical HVAC duct sealing in Greenwich runs $800 – $1,800 per system for standard flex-duct or accessible metal ductwork. Backcountry estates with unlined plaster chases, rusted galvanized sections, or multiple attic penetrations can run $1,500 – $2,400 per system due to the additional mastic volume, chase sealing, and pressure-testing time required.
Per-System Pricing for Multi-System Homes
Many Greenwich homes, especially in mid-country and backcountry, run two or three air handlers. We price each system separately so you’re not paying estate rates for a condo job, or vice versa. Each system gets its own written quote, its own scope of work, and its own after-documentation.
Pressure Testing Before and After
We verify every seal with a duct blaster or manometer test, documented on camera. You see the leakage rate drop in real numbers, not promises. This matters most in older homes where you cannot visually inspect ducts buried in plaster.
Duct Repair in Greenwich
Duct Repair in Greenwich addresses the physical damage that makes sealing impossible until the underlying problem is fixed: rusted-out galvanized sections, collapsed flex duct, disconnected trunk lines, or register boots pulled away from drywall by decades of vibration. In backcountry estates, we regularly find galvanized steel that has rusted through from chronic condensation in unheated attic chases. Downtown and Byram flex-duct condos more often show crushed or kinked runs from storage in tight mechanical closets, or tape that has dried and failed after fifteen summers.
Duct repair in Greenwich typically costs $400 – $1,200 per section for accessible flex-duct replacement or metal-patch work. Extensive galvanized replacement in estate attics, including insulation removal and reinstallation, can reach $1,500 – $3,000 depending on access difficulty and material type.
Rusted Galvanized Replacement
When we open a backcountry attic and find rusted galvanized duct, we don’t seal over it. We cut out the failed section, replace with properly sized sheet metal or flexible duct depending on the application, then seal the new connections. Sealing mastic applied over rust fails within a season.
Flex-Duct Re-Strapping and Support
Byram and downtown condos often have flex duct that has sagged off supports, creating kinks that choke airflow. Re-strapping with proper tension, replacing failed boots, and sealing with mastic restores design airflow without replacing the entire run.
Trusted Brands We Service in Greenwich
Our vans stock parts and sealing materials from Honeywell, Aprilaire, and Abatement Technologies, plus mastic and foil tape rated for the humidity swings Greenwich ducts endure. We don’t wait on supplier shipments for standard repairs. For negative-air containment during dusty chase work, we run Nikro equipment, the same machines commercial remediation crews use. If your system uses Honeywell zone dampers or Aprilaire media filters, we service those components as part of the sealing scope rather than treating ducts in isolation. Fast turnaround matters in a town where many homeowners maintain second properties and need work completed inside narrow windows.
Common Duct Sealing Problems We See in Greenwich Homes
- Condensation-damaged stone-chase ductwork in backcountry estates. Unheated attic spaces and stone-wall chases stay damp all winter. Sealing mastic applied over chronically wet galvanized metal fails within months, and black mold returns to the run. We address the moisture pathway first, then encapsulate with proper materials.
- Collapsed or kinked flex duct in downtown and Byram condos. Tight mechanical closets and long unsupported runs cause sagging that chokes airflow. The fix is re-strapping and boot sealing, not chase encapsulation, and pricing should reflect that difference.
- Multiple systems treated as one flat job. A three-system backcountry estate with long attic runs and zone dampers requires per-system scoping, per-system sealing, and per-system pressure testing. Lumping it together means some runs get skimmed while others leak for another decade.
- Failed tape and dried mastic on 15 – 20-year-old flex duct. Greenwich’s humidity cycles accelerate adhesive failure. We remove old tape entirely rather than layering over it, then apply mastic and foil tape rated for the local climate.
Pricing for Duct Sealing in Greenwich, CT
Here’s what duct sealing actually costs in this market:
| Service Scope | Typical Range in Greenwich |
|---|---|
| Standard flex-duct sealing (1 system, accessible) | $800 – $1,400 |
| Metal duct sealing with chase encapsulation | $1,200 – $1,800 |
| Backcountry estate: rusted galvanized + chase work | $1,500 – $2,400 |
| Duct repair (section replacement, per area) | $400 – $1,200 |
| Multi-system home (per additional system) | $700 – $1,600 |
What moves the number: accessibility (crawlspace vs. walk-in attic), duct material (flex vs. galvanized vs. ductboard), number of systems, and whether repair precedes sealing. We inspect first, write the price, and get your approval before any work starts. No per-vent add-ons, no equipment charges that appear after the van arrives. Estimates are free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Greenwich
Our crews regularly work in Cos Cob, Riverside, Old Greenwich, and Stamford. If you’re on the border or manage multiple properties across the area, we can coordinate scheduling from our Hartford office to minimize disruption. Our Duct Sealing team covers the full shoreline corridor with the same per-system pricing and written guarantee.
Serving Greenwich, CT - Our Local Coverage Area
We’re based in the Greenwich 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 Greenwich
Backcountry estates often have unlined duct chases inside plaster walls and rusted galvanized trunk lines through unheated attics, requiring chase encapsulation, moisture mitigation, and extensive mastic work. Byram condos typically need re-strapping and boot sealing on accessible flex duct. The labor hours and material volumes differ by a factor of two or more. Call (361) 326-5060 for an exact quote on your specific system.
We use a combination of pressurized fog testing to locate leaks, borescope cameras where access ports exist, and strategic chase encapsulation with mastic and foil tape at known penetration points. In a mid-country estate off Round Hill Road, our techs found a 1930s forced-air retrofit with unlined duct chases buried in plaster and a rusted galvanized trunk running through an unheated attic; we performed source removal under negative pressure, sealed the chase penetrations and attic run with mastic and foil tape, and verified leakage drop with a before-and-after pressure test documented on camera for the homeowner. You receive photos and pressure numbers, not a handshake.
A written invoice with the agreed price, before-and-after pressure test results in CFM25 or Pascal leakage rates, dated photos of accessed and sealed areas, and a copy of the 365-Day Done Right Promise. For multi-system homes, each system gets separate documentation. This matters in Greenwich’s larger estates where work is spread across multiple attics and mechanical rooms, and where homeowners may not personally inspect every space.
Yes. Coastal New England’s humidity cycles cause expansion and contraction in metal duct seams, accelerate adhesive failure on tape, and create chronic condensation in unconditioned attic spaces that rusts galvanized steel and breeds mold. We specify mastic and foil tape rated for high-humidity, freeze-thaw environments, not hardware-store products that fail in two seasons.
Yes, and we price each system separately so you know exactly what each costs before work starts. Many mid-country and backcountry Greenwich homes run two or three air handlers. Our crew scopes each system, writes per-system prices, and completes all agreed work in one visit when possible. Call (361) 326-5060 to schedule a multi-system inspection.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Greenwich since 2004.