Fast, Reliable Duct Repair & Sealing Across Exeter
How much does duct repair and sealing cost in Exeter, NH? Most homeowners pay between $275 and $850 depending on whether we’re sealing accessible joints with mastic or replacing collapsed flex runs behind walls. Thomas Hernandez and our crew typically reach Exeter properties within 45 minutes from Lowell, and we carry enough stock to finish most repairs same-day. If you’re smelling musty air from your vents or your upstairs rooms won’t heat evenly, there’s a decent chance your ductwork is pulling in damp cellar air through gaps you can’t see.
We’ve been working in Exeter long enough to know the pattern: colonial homes on Front Street, Water Street, and around the historic district have forced-air systems that were shoehorned into 200-year-old structures decades after they were built. That retrofit ductwork—often running through uninsulated stone cellars near the Squamscott River—was never designed to handle the humidity this estuary town throws at it. Our Duct Repair & Sealing team treats these as moisture-remediation jobs, not just maintenance calls. Call (877) 517-5646 for a free estimate.
Why Titan Air Duct Cleaning Lowell Is Exeter’s Preferred Duct Repair & Sealing Company
Thomas Hernandez shows up—as the owner and the technician doing the work. That matters in Exeter, where a generic crew from a national franchise won’t recognize that your 1960s sheet-metal return duct is routed through a flooded stone cellar until they’ve already quoted you wrong. Fourteen years in this specialty means we’ve seen the exact furnace plenum configurations common in Rockingham County colonials and capes.
Our 389 verified reviews averaging 4.7 stars include plenty from Exeter homeowners who found us after other companies walked away from tricky historic-system jobs. We’re not guessing at what’s behind your walls. We carry Rotobrush, Nikro, and Abatement Technologies equipment—the same platforms used on commercial remediation jobs—and we apply that capability to residential duct repair in Exeter’s older housing stock.
From cleaning to repair to sealing, your duct system gets handled start to finish. No subcontracted crews. No delegating to someone who wasn’t in your basement to see the actual problem.
Our Duct Repair & Sealing Services in Exeter
Mastic Sealant Application
In Exeter’s climate, tape fails. The elevated humidity from the Squamscott River and Great Bay estuary degrades standard duct tape within a season or two, leaving gaps that pull in damp cellar air and waste conditioned air. We seal joints, plenum connections, and transition points with professional-grade mastic sealant—brush-applied for full penetration into irregular surfaces that tape can’t grip. A typical mastic sealing job for accessible ductwork in Exeter runs $275–$450. For homes in the historic district with multiple unsealed transitions where metal meets vintage furnace plenums, costs can reach $600–$850 depending on linear footage.
Metal Duct Repair
Exeter’s mid-century ranch and cape-style homes on the outskirts—think neighborhoods off Route 108 and around the Exeter Country Club—often still run original 1950s–1970s galvanized sheet-metal duct systems. These accumulate decades of particulate, corrode at seams, and separate where supports have failed. We repair or replace sections, rehang sagging runs, and seal connections back to plenum. Metal duct repair in Exeter typically runs $350–$650 for single-run replacement, with full-system rehabilitation on larger homes reaching $800–$1,200.
Flex Duct Repair & Replacement
Flex duct installed in Exeter’s 1960s–1980s ranches and split-levels has reached end-of-life. The high ambient humidity accelerates liner degradation, and collapsed or separated flex behind walls creates hidden bypasses that circulate unfiltered, potentially mold-laden air. We replace flex branches with properly sized, insulated runs—often switching to metal where the original application was under-spec’d. Flex duct replacement in Exeter homes runs $200–$400 per branch, with full-system replacement on larger properties at $700–$1,100.
Duct Insulation
Here’s where Exeter’s geography really hurts homeowners: below-grade duct runs through uninsulated stone or brick cellars stay cold enough to condense moisture from humid summer air. That condensation feeds microbial growth inside your supply plenum. We insulate exposed metal ductwork with formaldehyde-free fiberglass wrap or closed-cell foam where space allows, stopping the temperature differential that creates condensation. Duct insulation work in Exeter typically costs $300–$550 for accessible basement or cellar runs.
What happens when you call
- 1
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.
Trusted Brands We Service in Exeter
We don’t show up hoping your hardware matches something in the van. Our equipment roster includes Nikro and Abatement Technologies systems for remediation-grade cleaning and access, plus Honeywell and Aprilaire components when we’re integrating air quality improvements with your duct repair. For Exeter’s older homes, that means we can source transition fittings and plenum adapters that fit vintage furnace configurations—not just standard modern specs. We stock mastic, mechanical fasteners, and insulation materials sized for the irregular chases common in historic construction. Most repairs don’t wait on parts.
Common Duct Repair & Sealing Problems We See in Exeter Homes
- Unsealed joints at vintage furnace plenums. In Exeter’s historic district, we regularly find original sheet-metal return ducts butted against 1970s-era furnace plenums with no mechanical seal—just gravity and rust holding them together. Your heated air leaks into the cellar; your system runs longer; your bills climb.
- Collapsed flex duct behind walls. The mid-century capes and ranches on Exeter’s east side often have flex branches that have separated from boots or collapsed entirely where insulation has compressed. Homeowners feel “dead” rooms with no airflow and don’t realize the duct is bypassing into the wall cavity.
- Microbial growth in below-grade stone cellar runs. Technicians working near the Squamscott floodplain routinely find visible mold on duct interiors in homes where owners had no idea. The persistent moisture from river-adjacent stone cellars creates conditions that biocide treatments alone can’t solve—sealing and insulation are required first.
- Insulation failure on exterior chase runs. Ductwork routed through uninsulated exterior walls or soffits in Exeter’s older homes loses heat rapidly in winter and sweats in summer. We re-insulate or reroute these runs to conditioned space where possible.
Pricing for Duct Repair & Sealing in Exeter, NH
Here’s what we’ve actually charged for recent Exeter jobs:
| Service | Typical Range in Exeter |
|---|---|
| Mastic sealant (accessible joints, single system) | $275 – $450 |
| Mastic sealant (historic district, multiple transitions) | $600 – $850 |
| Metal duct repair (single run replacement) | $350 – $650 |
| Metal duct rehabilitation (full system) | $800 – $1,200 |
| Flex duct replacement (per branch) | $200 – $400 |
| Flex duct replacement (full system) | $700 – $1,100 |
| Duct insulation (accessible cellar/basement runs) | $300 – $550 |
What moves you up or down in these ranges: accessibility (crawl space vs. open basement), linear footage, whether we’re working around asbestos-wrapped vintage ductwork, and whether the job requires Rotobrush cleaning before sealing. Every estimate we provide in Exeter is free and itemized. Call (877) 517-5646 to schedule.
We Also Serve Cities Near Exeter
Our service radius from Lowell covers the full Great Bay estuary area. We regularly handle duct repair and sealing in Kingston (where newer construction has its own flex-duct issues), Seabrook (salt-air corrosion on exterior hardware), Amesbury across the state line, and Merrimac with its mix of historic and mid-century stock. Same equipment, same owner-technician on site, same direct response.
Serving Exeter, NH — Our Local Coverage Area
We’re based in the Exeter 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 — Duct Repair & Sealing in Exeter
Newer homes have sealed duct systems designed as part of the structure; Exeter’s historic homes have ductwork retrofitted into spaces never intended for forced air, with unsealed joints that leak conditioned air and pull in damp cellar atmosphere. In a Colonial on Front Street, our crew found the original 1970s sheet-metal return duct running through an uninsulated crawl space that flooded during spring thaw. We sealed the entire run with mastic, replaced a rotted flex-branch with Rotobrush-cleaned metal, and insulated the chase to stop condensation. The homeowner had been complaining of musty odors for years—after our duct sealing, the indoor air quality improved immediately. Call (877) 517-5646 if you’re seeing similar symptoms.
Look for uneven heating between rooms, musty odors when the system runs, or dust accumulation at ceiling registers that exceeds normal levels. We also see rust staining on duct exteriors in Exeter’s humid cellars as an early indicator of internal condensation damage. Thomas Hernandez can inspect accessible runs with a borescope camera during a free estimate and show you exactly where your system is leaking. Call (877) 517-5646 to book.
Yes—this is one of the most specific risks in Exeter. Below-grade duct runs through stone or brick cellars near the floodplain stay damp year-round, accelerating corrosion at joints and creating conditions for mold colonization inside supply plenums. Even homes that haven’t flooded can have relative humidity 15–20% higher than inland Rockingham County properties. We address this with sealed, insulated ductwork that doesn’t give moisture a surface to condense on. Call (877) 517-5646 for an assessment of your cellar runs.
Collapsed flex duct typically requires replacement rather than repair—the liner and insulation have compressed or separated, and restoring original airflow geometry isn’t practical. We remove the failed section, verify the boot connection is intact, and install new properly-sized flex or switch to metal if the original was under-spec’d for the run length. Most Exeter cape flex replacements we do run $200–$400 per branch. Call (877) 517-5646 for a free estimate.
Mastic outperforms tape in Exeter’s humid environment by a wide margin. Tape adhesives degrade rapidly when exposed to the moisture levels common in Squamscott-adjacent cellars, peeling within a season or two. Mastic remains flexible, fills irregular gaps in vintage metalwork, and creates a mechanical bond that doesn’t rely on adhesive surface contact. We brush-apply it for full penetration at plenum transitions—the exact failure points we see most in Exeter’s historic homes. For a sealing assessment, call (877) 517-5646.
Ready to stop losing heated air into your cellar and start breathing cleaner air? Thomas Hernandez and our crew are available for free estimates across Exeter—call (877) 517-5646 today. We’ll inspect your system, show you exactly where it’s leaking, and give you an itemized quote with no pressure to commit.
Written by Thomas Hernandez, Owner at Titan Air Duct Cleaning Lowell, serving Exeter and the Great Bay estuary area since 2010.