Fast, Reliable Duct Repair & Sealing Across Boston
Duct repair and sealing in Boston typically costs $280-$650 for most residential jobs, with same-day or next-day service available throughout the city. Our Duct Repair & Sealing team knows the difference between a modern suburban system and what we’re actually walking into in a Back Bay brownstone. We’ve been driving to Boston from our office for over four decades, and we understand that your 1880s row house doesn’t behave like a 2005 colonial in the suburbs.
We answer our phones live, 24 hours a day. Call (844) 685-6342 and you’ll speak to a person who can dispatch a crew to Boston today.
Why Bellows Air Duct & Vent Co. Is Boston’s Preferred Duct Repair & Sealing Company
Boston homeowners have called us back for 42 years because we show up when we say we will and we don’t change the price at the door. Our technicians are background-checked, uniformed, and trained on the specific problems of retrofitted duct systems in historic housing stock.
We carry a strong local reputation built on word-of-mouth in neighborhoods from Beacon Hill to South Boston. Our customers mention the same things in their feedback: we explain what we’re doing before we start, we show camera footage of the actual problem, and we leave the price where we quoted it.
Response time to Boston is typically same-day for calls received before noon, next-day for afternoon requests. We don’t subcontract to random crews. The technician who arrives at your door in the North End or South End answers to our office, and our office answers the phone around the clock.
Our local knowledge matters because Boston buildings punish generic solutions. A sealing job that works in a 1990s ranch fails in a Beacon Hill brownstone where ducts run through 150-year-old brick chases. We’ve developed custom approaches for exactly these conditions.
Our Duct Repair & Sealing Services in Boston
Mastic Sealant
Mastic sealant is our primary sealing method for Boston’s irregular duct systems, but we don’t use it straight from the bucket. In historic row houses, we frequently encounter duct surfaces that expand and contract with Boston’s extreme humidity swings, from summer coastal moisture to winter’s dry forced-air heat. Standard mastic cracks under that movement. We fabricate flexible, reinforced mastic patches for irregular brick-chase surfaces, building up sealant in graduated layers that accommodate thermal movement. A typical mastic sealing job in Boston runs $320-$480.
Metal Duct Repair
Metal duct repair in Boston often means working with galvanized steel that was installed during mid-century conversions, sometimes connected to even older gravity systems. In a Beacon Hill brownstone, we tackled a duct repair job where an old gravity warm-air trunk was partially abandoned but still connected to the modern forced-air system, our crew sealed a 12-inch mastic-coated metal duct splice inside a closet cavity, restoring system pressure for a smart-home-integrated Aprilaire filter. Metal duct repairs in Boston typically range from $380-$620, depending on access and whether custom fabrication is needed.
Duct Insulation
Duct insulation in Boston serves two purposes: thermal efficiency and condensation control. The city’s coastal humidity means basement duct runs in older buildings sweat heavily in summer, creating the moisture conditions that accelerate mold and biofilm growth. We specify insulation rated for the humidity loads of Massachusetts Bay climate, not generic national products. Duct insulation work in Boston generally costs $450-$780 for typical residential systems.
Flex Duct Repair
Flex duct in Boston is usually found in additions, attic conversions, or partial renovations where rigid metal couldn’t be threaded through existing structure. We see crushed flex duct in South End brownstones where someone ran it through a too-small chase, and disconnected sections in North End buildings where vibration from old building systems has loosened clamps. Flex duct repair in Boston runs $280-$420.
Air Leak Repair
Air leak repair sounds simple until you’re working in a building where the original duct designer is unknown, the as-built drawings don’t exist, and the leaks are behind plaster lathe from 1890. We pressurize the system, use smoke testing to locate leaks, and repair with methods appropriate to the building’s construction. Typical air leak repair in Boston: $340-$560.
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.
Trusted Brands We Service in Boston
We stock parts and specify equipment from Honeywell, Aprilaire, and Abatement Technologies, the same brands serious HVAC contractors in Boston have relied on for decades. Honeywell zone controls and Aprilaire media filters integrate cleanly with the smart-home systems we’re increasingly asked to accommodate in renovated Back Bay and South End properties. We don’t guess at compatibility. We verify that what we’re installing works with what’s already in your system, and we carry common configurations on our trucks to avoid return trips.
Common Duct Repair & Sealing Problems We See in Boston Homes
- Abandoned gravity sections still connected to live systems. In Beacon Hill and the North End, technicians regularly encounter buildings where an old gravity warm-air or steam distribution system was only partially removed when forced air was added, leaving abandoned duct sections still connected to live plenums, trapping years of stagnant debris and sometimes asbestos-wrapped duct insulation that must be identified before any sealing work begins.
- Sealing over damp asbestos-wrapped duct insulation without proper abatement identification. We’ve been called to fix other contractors’ work where standard mastic was applied directly over deteriorating asbestos insulation, creating compliance issues and potential exposure hazards. We identify these materials before we start.
- Standard mastic failing on irregular brick-chase duct surfaces. Using standard mastic on irregular brick-chase duct surfaces that expand and contract with Boston’s humidity causes premature seal failure, usually within 18-24 months. We see this repeatedly in Back Bay and South End buildings where discount operators did the work.
- Fireplace chase and coal-chute duct routing creating inaccessible dead ends. In Boston’s historic row houses, duct systems are frequently routed through existing fireplace chases and coal-chute voids, creating sharp 90-degree turns and dead-end sections that trap debris and require custom-fabricated sealing patches, not off-the-shelf collars.
Pricing for Duct Repair & Sealing in Boston, MA
Here’s what duct repair and sealing costs in Boston’s market:
| Service | Typical Range |
|---|---|
| Mastic sealant (standard accessible ductwork) | $320-$480 |
| Metal duct repair (including custom fabrication) | $380-$620 |
| Duct insulation (thermal + condensation control) | $450-$780 |
| Flex duct repair/replacement | $280-$420 |
| Air leak detection and repair | $340-$560 |
| Comprehensive system sealing (whole-house) | $680-$1,200 |
What moves you within these ranges: access difficulty (crawlspace vs. open basement), whether we need custom-fabricated patches for irregular chases, and whether abandoned duct sections need proper capping and isolation. We inspect with a camera before we quote, so the price you hear is the price on the invoice. We also offer $50 off any repair over $250, a free second opinion on any written estimate, and a permanent 5% senior and veteran discount.
Call (844) 685-6342 for a free estimate. We’ll camera-inspect your system, show you what we find, and give you an upfront price before any work begins.
We Also Serve Cities Near Boston
Our service area extends to Boston‘s immediate neighbors: South Boston, Chelsea, Cambridge, and Winthrop. The same crews, same equipment, same upfront pricing. If you’re in ZIP codes 02113, 02114, 02115, or 02116, you’re in our primary Boston service zone.
Serving Boston, MA - Our Local Coverage Area
We’re based in the Boston 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 Boston
Beacon Hill row houses have duct systems routed through fireplace chases, coal-chute voids, and irregular wall cavities that create sharp turns and non-standard surface geometries. Standard collar-and-mastic sealing assumes round ductwork in open framing. We fabricate custom patches and use reinforced, flexible mastic formulations that accommodate the movement and irregular surfaces of these historic retrofits. Call (844) 685-6342 for a camera inspection and exact quote, estimates are free.
Yes. Many Boston buildings converted from gravity or steam heat contain asbestos-wrapped duct insulation that was never fully removed. We identify these materials during our pre-work camera inspection and advise on proper abatement protocol before any sealing begins. We do not apply sealant over deteriorating asbestos insulation. Call (844) 685-6342 and we’ll assess your specific situation at no charge.
Boston’s position on Massachusetts Bay produces persistently high coastal humidity through summer, which, combined with cold, dry winters forcing heavy heating-system use, creates strong seasonal moisture swings inside duct systems that accelerate seal degradation and mold growth. We specify humidity-tolerant mastic formulations and insulation rated for this specific climate load, not generic national products. Our 90-Day Done Right Promise covers any seal failure regardless of cause. Call (844) 685-6342 to schedule.
Yes. South End brownstones frequently have ducts routed behind original or period-matched woodwork that homeowners want preserved. We access through minimal, repairable openings, use borescope cameras to navigate blind cavities, and restore finishes without visible damage. We’ve worked behind coffered ceilings, paneled wainscoting, and built-in cabinetry. Metal duct repair in these conditions typically runs $480-$720 due to access complexity. Call (844) 685-6342 for an assessment.
The most common repair is capping and isolating abandoned gravity-system duct sections that were left connected when forced air was added, recirculating debris and creating pressure imbalances. We encounter this in roughly half the North End buildings we service. The repair involves identifying live vs. dead ductwork, fabricating custom caps, and sealing with mastic rated for the building’s humidity conditions. Typical cost: $340-$520. Call (844) 685-6342 for a free second opinion if you’ve been quoted elsewhere.
We’re here when you need us. Calls answered live, 24 hours a day. Same-day service available throughout Boston and surrounding communities.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Boston since 1984.