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 Somerville
Duct sealing in Somerville typically costs $800 – $2,400 for a whole-home system, with most triple-decker units falling in the $1,200 – $1,800 range depending on access and the condition of original ductwork. We dispatch to Somerville from our Boston office, and our crews know the difference between a Winter Hill three-decker and a Davis Square single-family when they pull up. Call (361) 326-5060 for a written estimate before any work starts.
We’ve been sealing ducts in Somerville long enough to know that the city’s housing stock doesn’t behave like newer construction. The triple-deckers off Highland Avenue, the converted Victorians near Union Square, and the post-war capes off Broadway each present their own duct problems. Original 1920s gravity-furnace round metal ducts, asbestos-wrapped trunk lines hidden behind plaster, and retrofitted flex duct in unheated attics are what we expect to find. Our Duct Sealing team treats every job by The Garrison Standard: arrive inside the window, price it in writing, do it by the book, leave the site clean.
Why Hollis Air Duct Cleaning Is Somerville’s Preferred Duct Sealing Company
Hollis Air Duct Cleaning has built its reputation in Somerville on showing up when we say we will and charging what we quoted. We’re part of the Garrison Partners family, in business since 2004, and every job we do in Somerville carries our 365-Day Done Right Promise in writing. If the seal fails within a year, we come back and make it right at no charge, including a free second visit.
Our technicians are background-checked and uniformed. You know who’s walking into your home before they arrive. Phones are answered by a live person 24 hours a day, seven days a week, not a voicemail loop. We’ve earned our standing in Somerville by handling the problems other crews walk away from: shared party-wall chases in triple-deckers, asbestos-wrapped ducts that need proper assessment, and freeze-thaw damaged joints in unheated attics that require real mastic work, not a quick tape patch.
Dispatch and scheduling are coordinated from our Boston office, but the crews serving Somerville live and work locally. They understand that Somerville’s dense lots and tight parking mean showing up prepared, not calling for directions from Route 93.
HVAC Duct Sealing in Somerville
HVAC Duct Sealing in Somerville means closing the gaps, cracks, and disconnected joints that let heated and cooled air escape before it reaches your rooms. In a typical Somerville triple-decker, we find supply trunks leaking into unheated basements, crushed flex runs feeding rear bedrooms, and return chases pulling air from all three units through the party wall. A proper sealing job here isn’t just about comfort. It’s about stopping your blower motor from working overtime, your utility bills from climbing, and your neighbor’s cooking smells from circulating through your vents.
Most Somerville homeowners call us for HVAC duct sealing after noticing uneven heating between floors, rooms that never reach temperature, or dust levels that spike when the system runs. In older homes near Davis Square and Winter Hill, we also see ice dam-related moisture damage that corrodes metal duct seams and loosens mastic from previous repairs.
Pricing for HVAC duct sealing in Somerville runs $800 – $2,400 for a complete system, with simpler single-floor jobs starting around $800 and full triple-decker treatments reaching the upper end. We always inspect first and give you a written price before any sealant touches your ducts.
Supply Trunk Sealing and Repair
The main supply trunk in a Somerville basement or unheated attic takes the worst of our freeze-thaw cycles. Original round metal ducts loosen at every joint. We clean the surface, apply duct mastic to every seam and joint, and replace failing fiberglass or asbestos tape with proper encapsulation where needed. In some Winter Hill homes, we’ve found supply trunks so leaky that more than 30% of heated air never reached the registers.
Return Chase Containment
Return ducts in Somerville triple-deckers often share a common chase inside the party wall. Sealing one unit’s return without addressing all three floors can push air and debris sideways into a neighbor’s system. We coordinate with all units when possible, or we isolate the chase with proper blocking so your sealing job doesn’t become someone else’s problem.
Duct Repair in Somerville
Duct Repair in Somerville addresses the physical damage that sealing alone won’t fix: crushed flex runs, disconnected collars, corroded metal that has rusted through, and sections of original ductwork that have pulled apart at the seams. We see this most often in homes where decades of renovations have left a patchwork of original metal, add-on flex, and improvised connections that no longer move air efficiently.
On a three-decker off Highland Avenue in Winter Hill, our tech found the first-floor supply trunk wrapped in failing asbestos tape and a crushed flex run feeding the second-floor rear bedroom. A camera inspection also showed the shared party-wall return chase pulling air from all three units. After negative pressure containment and source removal with agitation tools, we sealed the trunk seams and reconnected the crushed run so the blower motor wasn’t fighting a leaking duct system.
Duct repair in Somerville typically runs $400 – $1,500 depending on accessibility and the extent of replacement material needed. Jobs involving asbestos-wrapped ducts require proper assessment first, which we handle before quoting any repair work.
Metal Duct Restoration
Original 1920s round metal ducts in Somerville attics and basements can last another century if the seams are properly sealed and supported. We rehang sagging sections, replace corroded hangers, and apply fresh mastic to every longitudinal and transverse joint. Quick tape patches crack within a season here. We don’t use them.
Flex Duct Replacement
Add-on flex duct from retrofitted central air systems often gets crushed behind walls or kinked in tight chases. We replace damaged runs with properly sized, insulated flex and secure them with mechanical collars, not zip ties. In Somerville’s tight triple-decker framing, every inch of clearance matters, so we measure twice and cut once.
Trusted Brands We Service in Somerville
Our crews carry professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies, plus filtration and sealing products from Honeywell, Aprilaire, and Guardsman. For Somerville homeowners, this means we stock the parts and materials to complete most duct sealing and repair jobs in a single visit. We don’t run to the supply house mid-job and bill you for the time. Our rotary brush systems handle the agitation work inside original metal ducts, our negative-air machines maintain containment during asbestos-wrapped duct assessments, and our sealing mastics are rated for the temperature swings your attic ducts see every winter. When we quote a job in Somerville, we quote it with the actual materials we’ll use, not a generic allowance.
Common Duct Sealing Problems We See in Somerville Homes
- Freeze-thaw joint failure in unheated attics. Somerville’s cold, humid winters and hot, humid summers mean HVAC systems work overtime. The bigger issue is freeze-thaw cycles in unheated spaces that loosen every duct joint. Mastic-only patches crack within a season or two if the underlying metal keeps moving.
- Asbestos-wrapped trunk lines behind plaster walls. Many Somerville homes still have original duct wrap that can’t be sealed until it’s properly assessed and handled. Quick-visit crews often skip this step and seal right over failing material. We don’t.
- Disconnected flex runs in party-wall chases. In triple-deckers, crushed or disconnected add-on flex duct leaks into neighboring units through shared chases. Sealing one floor without coordinating the other two just moves the problem sideways.
- Corroded metal from coastal moisture and ice dams. Somerville’s proximity to the coast adds salt and moisture to the air, but the real damage comes from condensation during cooling season and ice dam leaks that rust out basement supply trunks.
Pricing for Duct Sealing in Somerville, MA
A typical duct sealing job in Somerville runs $800 – $2,400 for a complete residential system. Single-floor units in smaller homes or condos start around $800. Full triple-decker treatments with multiple access points and shared chase coordination typically land between $1,500 and $2,400. Duct repair, when needed alongside sealing, adds $400 – $1,500 depending on material and labor.
What moves the price: accessibility (crawl space vs. full basement), the condition of existing ductwork, whether asbestos wrap requires assessment, and whether we’re coordinating across multiple units in a triple-decker. We do not quote per-vent pricing. We quote one flat price per system, agreed in writing before work starts. That price does not move at the door.
Call (361) 326-5060 for a free estimate. We’ll inspect your system, explain what we found, and give you a written price you can take to another company for comparison.
We Also Serve Cities Near Somerville
Our crews work throughout the metro Boston area. We regularly handle Duct Sealing in Somerville and travel to Cambridge, Medford, Boston, and Everett for similar jobs. Each city’s housing stock presents its own challenges, but Somerville’s triple-decker concentration remains unique in the region.
Serving Somerville, MA - Our Local Coverage Area
We’re based in the Somerville 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 Somerville
Because the original builders ran all three units’ return ducts through a common chase inside the party wall, with little or no separation between them. When one unit’s blower runs, it creates negative pressure that pulls air from the shared space, including air from your neighbors’ returns. Sealing your ducts without isolating that chase or coordinating with all three units just changes where the air goes. We assess the chase configuration on every triple-decker job and recommend blocking or full coordination before we seal.
Original round metal ducts can be sealed effectively if the metal itself is intact, not rusted through, and properly supported. We clean the seams, apply fresh duct mastic rated for temperature cycling, and replace failing hangers. If sections have corroded from ice dam leaks or are structurally compromised, we’ll tell you during the inspection and quote replacement separately. Most Somerville attics we’ve worked in have salvageable metal with proper sealing. Call (361) 326-5060 for an exact assessment.
We stop and assess it properly. Asbestos-wrapped ducts cannot be sealed until the wrap condition is documented and handled according to Massachusetts requirements. We use negative pressure containment and proper personal protective equipment during any disturbance. Many quick-visit crews ignore the wrap or seal right over it. That creates a bigger problem later. We include asbestos assessment in our inspection when we see suspect material, and we’ll explain your options before quoting any work.
Yes. Somerville’s cold, humid winters and hot, humid summers create condensation inside ducts during cooling season, which corrodes metal seams and degrades mastic over time. The freeze-thaw cycles in unheated attics and basements are actually the bigger factor, causing thermal expansion and contraction that cracks seals within one or two seasons if the wrong materials are used. We specify mastic rated for the temperature swings your specific installation sees.
We inspect before we recommend either. If your ducts show heavy debris accumulation, pest intrusion, or visible mold, we clean first so the sealing surface is sound. If the ducts are relatively clean but you’re experiencing uneven temperatures, high bills, or dust blowout, sealing may be the right first step. In Somerville triple-deckers, we often find that cleaning reveals disconnected runs that need repair before sealing makes sense. Our inspection gives you the sequence, not a one-size-fits-all package. Call (361) 326-5060 to schedule a free look.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Somerville and the greater Boston area since 2004.