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 SeaTac
Duct sealing in SeaTac typically runs $400 – $900 for a whole-home system, with most jobs completed in a single visit after a written quote. Our Duct Sealing team dispatches from our Seattle office and carries the tools to handle SeaTac’s dense multifamily housing stock, from 1960s split-levels near Angle Lake to townhome complexes along International Boulevard where shared chases and restricted parking make access a puzzle. If you’re noticing uneven heating, rising energy bills, or that gray-black fuzz collecting on your registers, call us at (361) 326-5060. We’ll price the job in writing before any work starts, and every seal is backed by our 365-Day Done Right Promise.
Why Hollis Air Duct Cleaning Is SeaTac’s Preferred Duct Sealing Company
We’ve been working in SeaTac long enough to know that a truck parked on International Boulevard during rush hour misses the window, and that a technician without a camera scope has no business opening a chase in a 1990s townhome. Our crews arrive uniformed, background-checked, and equipped with Rotobrush rotary systems and Nikro negative-air machines, the same gear commercial crews run. The Garrison Standard means we quote in writing, seal by the book, and leave the site clean. Roy Castellanos built this operation on one rule: the price doesn’t move once it’s written down. That matters in a market where too many outfits quote low to get the van in the driveway, then find “problems” once they’re inside. Our 365-Day Done Right Promise covers every seal for a full year. If it fails, we come back at no charge, including a free second visit. No negotiation, no runaround.
Duct Insulation in SeaTac
Duct Insulation in SeaTac addresses a specific problem created by the city’s cool, wet marine climate and its aging housing stock: heat loss through uninsulated or poorly insulated duct runs, especially in damp crawlspaces beneath 1960s-1980s ramblers and split-levels near Angle Lake. When conditioned air leaks through thin or degraded duct walls before reaching the register, your furnace works longer, your bills climb, and the musty air from that wet crawlspace gets a free ride into your living space. In SeaTac’s market, adding or replacing duct insulation typically runs $300 – $700 depending on linear footage and access, with crawlspace work at the higher end due to confined conditions.
When Insulation Beats Sealing Alone
Some SeaTac homeowners call us for sealing when the real problem is thermal bleed through intact duct walls. We run a camera and pressure test to separate leakage from heat loss. If the ducts are sound but cold to the touch in your crawlspace, insulation with a proper vapor barrier stops condensation and mold growth better than mastic ever could.
Materials for Damp Pacific Northwest Crawlspaces
We use closed-cell foam and foil-faced fiberglass rated for below-grade moisture, not the hardware-store wrap that sags and breeds mold after one wet SeaTac winter. Every insulation job includes a written R-value guarantee and photographs of the completed run.
HVAC Duct Sealing in SeaTac
HVAC Duct Sealing in SeaTac is the mechanical process of closing leaks, reconnecting separated joints, and restoring pressure balance in forced-air systems that have been compromised by age, vibration from airport overflight, or sloppy original installation. The goal is simple: the air your furnace or heat pump conditions should reach the rooms you live in, not your attic, crawlspace, or your neighbor’s unit through a shared chase. For a typical SeaTac single-family home, HVAC duct sealing runs $400 – $750; multifamily units with shared systems or restricted access range $350 – $600 per unit, with whole-building assessments priced separately.
Camera Inspection Before Seal
We don’t guess where leaks live. Our techs feed a scope through the duct run to find disconnected collars, split flex duct, and gaps at plenum connections that visual inspection misses. In SeaTac’s 1990s townhomes, we’ve found separation points buried behind drywall that would have stayed hidden without it.
Negative Pressure Verification
After sealing with mastic and foil tape rated for HVAC temperatures, we run a negative pressure test to confirm the system holds. A sealed duct that still leaks is a failed job by our standard, and we don’t sign off until the numbers prove it.
Trusted Brands We Service in SeaTac
We stock parts and sealing materials from Abatement Technologies, Guardsman, and Aprilaire, which means most SeaTac jobs don’t wait on a parts run to Tacoma or Seattle. Our vans carry mastic compounds rated for damp Pacific Northwest conditions, foil tapes that hold through temperature swings, and HEPA filtration from Abatement Technologies to protect your air during the work. When your system needs a component we don’t have on the shelf, our Seattle office coordinates same-day or next-morning pickup. No ghosting, no “we’ll come back next week.”
Common Duct Sealing Problems We See in SeaTac Homes
- Disconnected flex duct collars in International Boulevard townhomes. The original flex duct in 1990s-2000s complexes was often jammed into tight shared chases with inadequate support. Vibration from HVAC cycles and airport overflight shakes joints loose over time. Sealing without a camera inspection misses these buried failures.
- Negative pressure pulling airport particulate between units. In multifamily buildings with shared return plenums, one unsealed joint creates a vacuum that draws the gray-black fuzz of jet exhaust and I-5 tire dust from neighboring units or common chases. Your registers stay dirty no matter how often you clean them.
- Compromised dryer vent stacks in Angle Lake condos. Shared vertical stacks allow lint migration between units. Sealing only the in-unit flex run leaves the stack pathway open, maintaining fire risk and recirculating moist, particulate-laden air.
- Mold-prone crawlspaces in 1970s split-levels near Angle Lake. Damp Pacific Northwest soil keeps crawlspaces wet year-round. Unsealed duct seams suck musty air and active mold spores directly into supply lines. Sealing stops the pathway; sanitizing handles what’s already inside.
Pricing for Duct Sealing in SeaTac, WA
A typical whole-home duct sealing in SeaTac runs $400 – $900, with most single-family homes falling in the $500 – $700 range. Multifamily units in International Boulevard or Angle Lake complexes start around $350 per unit for accessible systems, climbing to $600 when we need to coordinate building access, navigate restricted parking, or work within tight mechanical closets. What moves the number: linear footage of ductwork, number of identified leaks, crawlspace versus attic access, whether insulation replacement is needed, and if the job follows a camera inspection that reveals hidden separation. We quote one flat price per system, agreed in writing before any sealant touches your ducts. No per-vent pricing, no add-ons at the door, no “while we’re here” upsells. Call (361) 326-5060 for a free estimate. We’ll inspect, photograph, and price it on the spot.
We Also Serve Cities Near SeaTac
Our crews work throughout the Puget Sound region, including SeaTac and neighboring Seattle, Spokane, Tacoma, and Vancouver. Scheduling and dispatch are coordinated from our Seattle office, with local technicians assigned to minimize drive time and keep arrival windows tight.
Serving SeaTac, WA - Our Local Coverage Area
We’re based in the SeaTac 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 SeaTac
You’re likely pulling contaminated air through unsealed joints in a shared system. In SeaTac’s multifamily buildings, one disconnected collar in a common chase or return plenum creates negative pressure that draws airport particulate, road dust, and damp crawlspace air into your supply. Vacuuming registers only cleans what settled; sealing the leak stops what’s feeding it. Call (361) 326-5060 and we’ll camera the run to find the entry point.
Duct sealing addresses the in-unit flex run and connection to the stack, but a shared vertical stack requires coordinated assessment of the entire pathway. We seal your connection point and inspect the stack access with building maintenance when possible. If the stack itself is compromised, we document it with photos and recommend next steps. The full fix usually involves the HOA and a commercial dryer vent cleaning crew for the shared shaft.
Sealing stops the pathway, but if mold is already established in your duct interior, you’ll need mechanical cleaning and sanitizing first. We seal after source removal so spores aren’t trapped behind a new seal to bloom later. In SeaTac’s wet climate, we also evaluate whether duct insulation with a proper vapor barrier makes sense for your crawlspace. The written quote covers both options.
We coordinate arrival times that work with your building’s parking rules and bring compact equipment that fits through standard doorways. For mechanical closets, we remove access panels and use flexible camera scopes and sealing tools designed for confined spaces. If we need temporary parking clearance, we handle the logistics with your building management before we arrive, not after we’re circling the block.
Yes, if the sealing targets the leaks that are pulling that particulate into your system. The gray-black fuzz is a SeaTac signature, jet exhaust soot mixed with rubber tire dust from I-5 and SR-518. It enters through gaps in your duct envelope, not through your filter. We identify those entry points with camera inspection and pressure testing, seal them with mastic and foil tape, then verify the fix. Your registers stay cleaner because the contamination source is cut off, not because we cleaned what was already there. Call (361) 326-5060 for an exact quote – estimates are free.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving SeaTac and the greater Puget Sound region since 2004.