Fast, Reliable Duct Repair & Sealing Across Seattle
Most Seattle homeowners don’t realize their ducts are failing until the utility bill spikes or the registers start smelling like a damp basement. Duct repair and sealing in Seattle typically runs $280-$650 for standard jobs, with same-day service available when you call before noon. We’re familiar with the hillside lots, the vented crawl spaces, and the retrofitted ductwork that comes with them. Our Duct Repair & Sealing crew covers all of Seattle, from Ballard to Beacon Hill, and we answer the phone live, 24 hours a day, at (844) 685-6342.
Why Bellows Air Duct & Vent Co. Is Seattle’s Preferred Duct Repair & Sealing Company
We’ve been at this since 1984, and Ray Castillo has kept the same standard through four decades: show the homeowner what you’re doing, quote it upfront, and stand behind it. In Seattle, that means something specific. We know the ZIP codes where the problems hide - 98107 in Ballard, 98108 on Beacon Hill, 98109 up Queen Anne - and we know why a duct camera isn’t optional in this market.
Our technicians are background-checked, uniformed, and equipped with Rotobrush cameras on every truck. Most Seattle jobs finish in a single visit. The price we quote on the phone is the price on the invoice. No bait coupons, no upsell at the door. Our 90-Day Done Right Promise covers every repair: if it’s not right, we return at no charge, no paperwork, no arguing. That’s been our way for over 42 years.
Calls don’t go to voicemail. A live person answers, day or night. For Seattle homeowners who’ve already been burned by a low-bid contractor, that matters.
Our Duct Repair & Sealing Services in Seattle
Duct Sealing
Seattle’s older homes leak air like a sieve. In the Craftsman bungalows and Tudor Revivals around Capitol Hill and Fremont, retrofitted ductwork from the 1950s-70s was often joined without proper mastic sealant. We seal every joint with professional-grade mastic and reinforced tape, then pressure-test the system to verify the fix. A typical duct sealing job in Seattle runs $350-$550 for a single system, and most homeowners see immediate improvement in room-to-room airflow.
Flex Duct Repair
Since the 2021 Pacific Northwest heat dome, Seattle saw a rush of ducted heat pump installations in homes that never had forced air. The flex duct installed in that hurry is now failing - sagging in damp crawl spaces, tearing at sharp bends, pulling loose from collars. We replace collapsed or damaged flex duct with properly supported, insulated runs rated for Seattle’s humidity. Flex duct repair in Seattle typically costs $180-$340 per section, depending on crawl space access.
Metal Duct Repair
Galvanized steel ductwork in Seattle’s pre-war homes corrodes slowly but steadily in high-humidity crawl spaces. We patch small holes, replace rusted sections, and reconnect separated joints with mechanical fasteners and mastic sealant. Where metal duct has been colonized by mold, we remove the affected section rather than attempting surface treatment - it’s the only repair that lasts in this climate. Metal duct repair in Seattle generally runs $250-$480.
Duct Insulation
Uninsulated ductwork in Seattle’s vented crawl spaces condenses moisture onto cold metal surfaces eight months of the year. We wrap supply ducts with formaldehyde-free fiberglass insulation or install pre-insulated flex duct where appropriate. Proper insulation prevents the condensation that feeds mold growth and reduces the thermal losses that drive up heating bills through Seattle’s long heating season. Duct insulation in Seattle typically runs $400-$700 for a full system.
Mastic Sealant Application
We don’t trust tape alone in Seattle’s wet climate. Mastic sealant, applied with a brush at every joint and seam, remains flexible and airtight for decades. It’s the standard we apply on every sealing job, and it’s particularly critical at the poorly fitted connections common in retrofitted Craftsman homes. Mastic work is included in our standard duct sealing pricing.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
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 Seattle
We stock parts and specify equipment from the brands serious HVAC contractors trust: Rotobrush for duct camera inspection and mechanical cleaning, Abatement Technologies for HEPA containment and air scrubbing, and Aprilaire for whole-home humidity control and filtration. For Seattle’s mold-prone conditions, we also apply Guardsman EPA-registered biocides where mechanical cleaning alone won’t suffice. Having these parts on the truck means most Seattle repairs don’t wait for a second trip.
Common Duct Repair & Sealing Problems We See in Seattle Homes
- Collapsed flex-duct from the 2021 heat pump rush. Uninsulated flex duct installed quickly in damp crawl spaces has begun to sag, tear, and bypass conditioned air entirely. We find this weekly in homes across 98105 and 98106.
- Mold in fiberglass-lined supply ducts. Seattle’s sustained 75-85% indoor relative humidity allows mold colonization within months of system disuse. Unlike dry-climate markets where dust is the primary concern, Seattle jobs routinely require biocide application after cleaning.
- Leaky, mastic-free joints in retrofitted 1950s ductwork. Poor connections in Craftsman basements and crawl spaces waste 20-30% of airflow. The homeowner feels it as cold rooms and high bills.
- Hidden mold reservoirs in hillside crawl spaces. In Queen Anne and Beacon Hill, retrofit duct runs travel 20-30 feet through vented crawl spaces inches above damp soil. These sections are invisible from the registers, and they’re almost always the source of persistent musty odors.
Pricing for Duct Repair & Sealing in Seattle, WA
We’re straightforward about numbers because we don’t play the coupon game.
| Service | Typical Range in Seattle |
|---|---|
| Flex duct repair (per section) | $180 - $340 |
| Metal duct repair (per section) | $250 - $480 |
| Duct sealing (single system) | $350 - $550 |
| Duct insulation (full system) | $400 - $700 |
| Camera inspection with full report | $150 - $225 |
What moves the price: crawl space access difficulty, extent of mold contamination requiring biocide treatment, and whether the home needs new duct supports or hanging hardware. We inspect with a camera first, show you what we find, and quote before any work begins. Estimates are free. We also honor our standing offers: $50 off any repair over $250, free second opinion on any written estimate, and a permanent 5% senior and veteran discount.
We Also Serve Cities Near Seattle
Our service area extends across King County. We regularly repair and seal ductwork in Seattle as well as Bellevue, Kirkland, Shoreline, and Redmond. The same crew, same equipment, same upfront pricing applies whether we’re working on a Capitol Hill Craftsman or a Bellevue split-level.
Serving Seattle, WA - Our Local Coverage Area
We’re based in the Seattle 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 Seattle
Seattle’s marine west coast climate sustains 75-85% indoor relative humidity year-round, even without rain, which accelerates mold growth in duct interiors and corrodes metal components faster than in dry climates. The dense stock of pre-WWII homes with retrofitted ductwork in damp crawl spaces compounds the problem. Call (844) 685-6342 for a free inspection - we’ll show you exactly what your system faces.
Collapsed or mold-contaminated flex duct in vented crawl spaces is the repair we perform most often in these neighborhoods. The hillside lots force long duct runs through damp, unconditioned spaces just inches above soil. Last month, our crew responded to a Queen Anne Craftsman (ZIP 98109) where the homeowner reported musty smells from the registers. Using our Rotobrush camera, we discovered a 20-foot flex duct section in the crawl space had partially collapsed and was lined with mold. We replaced it with insulated metal duct, applied mastic sealant at every joint, and treated the interior with an EPA-registered biocide. The homeowner reported fresh, clean air the same day. If your registers smell damp, the problem is likely below the floorboards.
Yes - if your home was built before 1945 and has retrofitted forced-air ductwork, a camera inspection is the only way to assess the condition of hidden runs in crawl spaces. We offer camera inspections from $150-$225, and we show you the footage before quoting any repair. Call (844) 685-6342 to schedule.
Yes. We replace sagging, torn, or poorly supported flex duct with properly hung, insulated runs that withstand Seattle’s humidity. Many of these 2021 installations used uninsulated flex in unconditioned spaces, a combination that fails quickly here. We’ll inspect, quote, and typically complete the repair in one visit.
We specify Rotobrush for camera inspection and mechanical cleaning, Abatement Technologies for containment and air scrubbing, and Aprilaire for humidity control and filtration. For biocide treatment in mold-contaminated systems, we use Guardsman EPA-registered products. These are the same brands specified by serious HVAC contractors nationwide, and we stock them on every Seattle truck.
Ready to stop losing heated air to your crawl space? Call Bellows Air Duct & Vent Co. at (844) 685-6342 for a free estimate. We’ll be there when we say, we’ll show you what we find, and we’ll stand behind the repair - in writing, for 90 days, no paperwork and no arguing if something needs adjustment. That’s been our promise since 1984.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving Seattle since 1984.