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.
Fast, Reliable Duct Sealing Across North Bend
North Bend sits where the Snoqualmie Valley narrows against the Cascade foothills, and that geography shapes everything about how air moves through your home. We’re the crew Hollis Air Duct Cleaning sends up from our Seattle office when homeowners from the valley floor to the ridge lines call about rooms that never heat evenly, utility bills that climb without explanation, or the faint whistle of air escaping behind walls. Our technicians know the difference between a 1990s tract home off North Bend Way and a retrofitted cabin near the Middle Fork, and we price every duct sealing job in writing before we touch a single register. If your forced-air system is working harder than it should, call us at (361) 326-5060. We’ll give you a free estimate and a written quote that doesn’t move at the door.
Why Hollis Air Duct Cleaning Is North Bend’s Preferred Duct Sealing Company
We’ve been handling Duct Sealing work long enough to recognize the patterns that repeat in this valley. The cottonwood pollen that coats everything in May finds every gap in poorly sealed return plenums. The fine glacial silt that drifts in from the South Fork corridor abrades blower motors when it gets pulled through leaking ductwork. Our crew has sealed ducts in homes from the older neighborhoods near downtown North Bend to the newer builds climbing toward Mount Si, and we arrive with that context already in mind.
Our customers in North Bend leave feedback that mentions the same things: the technician showed up inside the window, explained what they found with a camera, and the final price matched the written quote. That’s The Garrison Standard in practice, not just on paper. Our phones are answered by a live person 24 hours a day, seven days a week, so you’re not waiting through a voicemail loop when you’ve got a question about your appointment. Every technician we send to North Bend is background-checked, uniformed, and accountable to the 365-Day Done Right Promise. If our seal fails within a year, we come back and make it right at no charge, including a free second visit. No negotiation, no runaround.
Duct Sealing Services in North Bend
Duct Sealing Services in North Bend address a problem most homeowners don’t know they have until the symptoms become impossible to ignore. Your ductwork is a closed-loop system, but age, vibration, and the original installation shortcuts common in 1990s and 2000s valley construction open gaps at joints, seams, and connections to the plenum. In North Bend’s damp climate, those leaks do more than waste heated or cooled air. They pull in crawl-space moisture, pollen, and that distinctive valley silt, distributing it through every room. A typical whole-house duct sealing job in North Bend runs $1,200 – $2,400 depending on system size and accessibility, with smaller partial repairs starting around $450. We use mastic sealant and metal-backed tape rated for the temperature swings your ducts see, not the hardware-store foil tape that peels off in our humidity.
Leak Detection and Mapping
Before we seal anything, we pressurize your duct system and measure airflow loss at each register and return. In older North Bend homes near the river, we regularly find 25 – 35% leakage in the duct runs that pass through unconditioned crawl spaces. The test takes about 45 minutes, and you’ll see the numbers yourself.

Mastic Sealing of Joints and Plenums
We brush on fiberglass-reinforced duct sealing mastic at every joint, seam, and connection point. Unlike tape alone, mastic remains flexible through decades of thermal cycling, which matters in North Bend where heat pumps switch between heating and cooling modes frequently during our mild, damp shoulder seasons.

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.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Duct Insulation in North Bend
Duct Insulation in North Bend is often the missing half of the equation after sealing is complete. Even perfectly sealed ducts lose efficiency when they pass through unconditioned attics or crawl spaces, and in our climate that means condensation on cold metal during humid months and heat loss that your heat pump compensates for by running longer cycles. We wrap sealed ducts with formaldehyde-free fiberglass insulation, typically R-6 or R-8 depending on location, and secure it with vapor-barrier jacketing that holds up in our wet environment. A typical duct insulation project in North Bend runs $800 – $1,800 for a complete system, or $300 – $600 when combined with sealing work on the same visit. Homes near the Snoqualmie River with elevated crawl-space humidity see the fastest payback, since insulated ducts don’t sweat and don’t grow the mold colonies we’ve found in too many valley-floor inspections.
Crawl-Space and Attic Runs
These are the hardest-working and most neglected ducts in any North Bend home. We pull back old, water-stained insulation, seal the metal underneath, and reinstall with proper vapor barriers. In flood-prone areas near the Middle Fork, we also check for silt accumulation that indicates previous water intrusion.
Plenum and Trunk Line Wrapping
The main distribution boxes and trunk lines near your air handler move the most air and suffer the greatest temperature differential. We insulate these with higher-R material and sealed seams, which in our experience reduces the temperature swing that causes expansion noise in North Bend’s older systems.
Trusted Brands We Service in North Bend
Our vans carry sealing and insulation materials from Abatement Technologies and Guardsman, plus filtration upgrades from Aprilaire for homeowners who want to address air quality at the same time we stop the leaks. We don’t order parts from a catalog when you’re waiting. Our Seattle office stocks the mastics, tapes, and insulation jackets we use most, so a North Bend job that needs material we didn’t anticipate doesn’t turn into a second visit. When we recommend a product, it’s because we’ve watched it hold up in this valley’s specific conditions, not because it’s the default option from a national distributor.
Common Duct Sealing Problems We See in North Bend Homes
- Pollen infiltration through crawl-space leaks. North Bend’s spring cottonwood and cedar pollen loads are among the heaviest in King County. When return ducts pull air from leaky seams in a crawl space, that sticky pollen coats the inside of your ductwork and becomes a reservoir that releases for months after the trees are done blooming.
- Glacial silt abrasion in valley-floor homes. After any moderate rise on the Snoqualmie or its tributaries, we find a thin layer of fine river silt inside return ducts. It looks like ordinary dust but is abrasive enough to wear blower motor bearings prematurely when it circulates through a leaky system.
- Undersized ductwork in retrofitted cabins and farmhouses. Older homes near the river that converted from wood heat to forced air often have ductwork too small for modern heat pumps. The resulting high static pressure blows apart original seals and creates new leaks at every joint.
- Condensation damage from uninsulated ducts in humid crawl spaces. North Bend’s year-round humidity, especially in shaded lots near the foothills, causes cold supply ducts to sweat. Water drips onto mastic and tape, degrading the seal and starting the cycle over again.
Pricing for Duct Sealing in North Bend, WA
We don’t quote per-vent teaser prices that balloon once we’re inside your home. A typical whole-house duct sealing job in North Bend runs $1,200 – $2,400. Partial sealing of a single zone or problem area starts around $450. Duct insulation added to the same visit typically adds $300 – $600 for standard systems, or $800 – $1,800 for a full standalone insulation job. What moves the price: the total linear feet of ductwork, how much of it is accessible (crawl space versus finished basement), the condition of existing seals, and whether we find damage that needs repair before sealing makes sense. We give you one flat price per system, agreed in writing before work starts. That price includes the pressure test, all materials, and cleanup. Estimates are free, and there’s no charge for us to look and tell you honestly whether sealing is worth it for your specific situation. Call (361) 326-5060 to schedule.
We Also Serve Cities Near North Bend
Our crews work throughout the Snoqualmie Valley and the I-90 corridor, including Air Duct Cleaning in North Bend and surrounding communities. We regularly schedule Dryer Vent Cleaning in North Bend on the same visit as duct sealing for homeowners who want their full system handled at once. If you’re in Snoqualmie, Hobart, Issaquah, or Maple Valley, the same pricing structure and The Garrison Standard apply. Dispatch is coordinated from our Seattle office, and we route crews to minimize your wait without the overhead of maintaining a separate shop in every town.
Serving North Bend, WA - Our Local Coverage Area
We’re based in the North Bend 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 North Bend
A whole-house duct sealing job in North Bend typically runs $1,200 – $2,400, which falls in line with Snoqualmie and Issaquah pricing but can run slightly higher than Maple Valley due to the prevalence of crawl-space work in our older, river-adjacent housing stock. Call (361) 326-5060 for an exact quote on your home. Estimates are free.
Yes, we seal ducts from the ridge-line developments near Mount Si down to the valley-floor homes along the South Fork Snoqualmie River, including the older cabins and farmhouses with retrofitted systems that need the most attention. Call (361) 326-5060 to schedule.
We typically schedule North Bend appointments within 3 – 5 business days, with flexibility for homeowners who need coordination with other trades. Our Seattle office dispatches crews specifically for valley jobs, so you’re not waiting for a technician to finish in Bellevue first. Call (361) 326-5060 to check current availability.
We don’t classify duct sealing as an emergency service, but our phones are answered by a live person 24/7, and we’ll move you to the front of the schedule if you’ve got a situation like a disconnected trunk line or a major leak that’s making your system unusable. Call (361) 326-5060 and we’ll tell you honestly whether you need us tomorrow or can wait for standard scheduling.
Every duct sealing job is backed by our 365-Day Done Right Promise in writing. If our seal fails within a full year, we return and make it right at no charge, including a free second visit. No pro-rated gimmicks, no arguments about whether the leak was “pre-existing.” Call (361) 326-5060 if you have questions about what’s covered.
Ready to stop heating your crawl space and start heating your home? Call Hollis Air Duct Cleaning at (361) 326-5060 for a free, written estimate on duct sealing in North Bend. We’ll show you where your system is leaking, explain what sealing will fix, and give you one flat price that doesn’t change when we arrive.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving North Bend and the Snoqualmie Valley since 2004.




Before
After
Before
After
Before
After