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 Glendale
Duct sealing in Glendale typically costs $350 – $850 for a single-system home, with most jobs completed in one visit. If your registers still smell like wildfire smoke months after cleaning, or your utility bills keep climbing despite a newer HVAC unit, the problem is almost always air leaking from unsealed joints and disconnected plenums.
We serve Glendale from our Los Angeles office, dispatching crews to neighborhoods from downtown’s 91201 ZIP up through the Verdugo foothills in 91206 and 91208. Our technicians know the parking restrictions on Chevy Chase Canyon Drive, the tight access in pre-war bungalow crawlspaces, and the shared mechanical systems in Glendale’s multi-unit buildings. When you call (361) 326-5060, a live person answers, schedules your free estimate, and sends a background-checked, uniformed technician who arrives inside the quoted window with a written price in hand.
Why Hollis Air Duct Cleaning Is Glendale’s Preferred Duct Sealing Company
We’ve been part of the Garrison Partners family since 2004, and our Duct Sealing team has worked Glendale’s specific housing stock long enough to know what fails here. The pre-1940 bungalows south of Colorado Boulevard weren’t built for central air; their floor-furnace retrofits leave return plenums half-sealed at best. The 1960s ranchers in the hills have flex duct that disconnects at attic air handlers after years of Santa Ana wind cycles. We don’t guess. We inspect with cameras, price in writing, and seal with mastic and foil tape rated for California mechanical code.
Our 365-Day Done Right Promise covers every sealing job in writing. If a joint fails, a flex run disconnects, or ash smell returns through a plenum we sealed, we come back at no charge. That includes a free second visit, not a negotiation. Roy Castellanos built this standard into Hollis because homeowners in Glendale have already dealt with enough moving targets from contractors.
Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues, no waiting until Monday to schedule. Our technicians are background-checked and uniformed; you know who’s walking into your home before they arrive. And the price we write down before any work starts is the price you pay. It does not move at the door.
Duct Repair in Glendale
Duct Repair in Glendale addresses the physical damage that makes sealing necessary: collapsed flex runs, rusted metal joints, disconnected plenums, and holes from rodents or remodeling work. In Glendale’s 91201-91204 ZIP codes, we regularly find original 1950s-era galvanized ductwork with separated seams that were taped decades ago and have since dried, cracked, and fallen away. The hillside homes in 91206 and 91208 more often show crushed or kinked flex duct from attic work or storage.
A typical Duct Repair in Glendale runs $280 – $650 depending on access, material type, and whether we need to replace sections or can seal existing runs. We always inspect with a camera first, show you the damage, and write the price before touching anything.
When Repair Becomes Replacement
Some Glendale ductwork is too far gone to repair cost-effectively. If your metal ducts are rusted through or your flex runs are brittle and cracking across multiple sections, we’ll tell you straight and price replacement against repair so you can decide. We don’t patch what should be replaced just to collect a smaller invoice today.
Attic Air Handler Disconnections
The attic-mounted air handlers common in Glendale’s 1960s-70s tract homes create a specific failure point. The flex connections between handler and plenum work loose over time, especially after Santa Ana wind events that pressurize attic spaces. We secure these with mechanical fasteners plus mastic, not tape alone, because tape fails under thermal cycling.
Air Duct Sealing in Glendale
Air Duct Sealing in Glendale closes the gaps that let conditioned air escape and contaminated air enter your HVAC loop. We use duct sealing mastic, a water-based compound that remains flexible after curing, reinforced with foil tape at high-stress joints. For homes in the Bobcat Fire ash corridor, particularly 91201 and 91202, sealing the return plenum and attic connections is what stops wildfire ash from re-entering the system months after visible cleanup.
Typical Air Duct Sealing in Glendale costs $350 – $850 for a single-system residential job. Multi-unit buildings with shared stacks or complex access may run higher; we price those after inspection, never with a teaser quote that balloons on arrival.
Return Plenum Sealing
The return plenum is the box that connects your return ducts to the air handler. In Glendale’s pre-war bungalows, these were often cobbled together during floor-furnace retrofits with gaps large enough to pull attic air, crawlspace dust, or wildfire ash directly into your breathing air. We seal every seam, every penetration, and every connection point with mastic rated for the temperature swings of attic mounting.
Flex Duct Connection Points
Flex duct connects to metal plenums with collars that loosen over years of vibration and thermal expansion. In Glendale’s hillside homes, Santa Ana winds add attic pressurization that accelerates this loosening. We remove failed tape, clean the collar, apply mastic, and secure with a draw-band plus secondary tape wrap. The connection stays sealed through the next wind event.
Trusted Brands We Service in Glendale
Our equipment roster includes Nikro negative-air machines for controlled debris removal, plus filtration and sealing products from Honeywell and Aprilaire. We stock mastic, foil tape, and flex duct connectors for common Glendale system configurations, including the older Carrier, Trane, and Lennox units we see frequently in 91201-91204 homes. Because we carry parts rather than ordering them, most Glendale sealing jobs finish same-visit without a return trip. If your system uses Abatement Technologies HEPA filtration or Guardsman sealing compounds, we match those specifications on replacement materials so your warranty stays intact.
Common Duct Sealing Problems We See in Glendale Homes
- Wildfire ash re-entrainment through unsealed return plenums. After the 2020 Bobcat Fire, homes in 91201 and 91202 called us months after duct cleaning because ash smell persisted. The visible dust was gone, but unsealed plenum gaps pulled attic ash back into the HVAC loop every time the system cycled. Sealing the plenum broke the cycle.
- Disconnected flex at attic air handlers in hillside homes. The 91206 and 91208 ranchers built into the Verdugo foothills often have air handlers mounted in attics with long flex runs. Vibration, thermal cycling, and Santa Ana pressurization disconnect these at the collar. We find gaps pulling 140-degree attic air into the system, killing efficiency and filtering nothing.
- Tight street access blocking negative-pressure equipment. Chevy Chase Canyon Drive and similar hillside roads don’t accommodate our full Nikro negative-air truck setups. We stage equipment at curb or through apartment windows and seal with handheld tools, mastic, and portable cameras rather than skipping the job or charging extra for access difficulty.
- Shared dryer vent stacks in multi-unit Glendale buildings. The stacked vent systems common in Glendale’s denser neighborhoods have junctions that were never sealed at installation. Lint re-enters hallways, fire risk accumulates, and individual unit cleanings fail because the stack itself leaks. We seal these junctions with fire-rated mastic accessible through cleanout ports.
Pricing for Duct Sealing in Glendale, CA
Duct sealing in Glendale runs $350 – $850 for most single-family homes with one HVAC system. Two-system homes or those with complex attic access typically fall in the $650 – $1,200 range. What moves the price: the linear footage of ductwork, number of connection points requiring sealant, whether we need to repair or replace damaged sections first, and access difficulty in hillside neighborhoods where tight parking and steep lots add labor time.
We do not quote per-vent pricing. That structure invites bait-and-switch, and it’s not how we work. We price per system, agreed in writing before any sealant is opened. Every estimate is free, every price is flat, and every job carries the 365-Day Done Right Promise. Call (361) 326-5060 for your exact quote.
We Also Serve Cities Near Glendale
Our crews work Duct Sealing in Glendale and surrounding communities including Burbank, West Hollywood, Altadena, and Pasadena. Each city has distinct housing stock and duct configurations; we adjust our inspection and sealing approach accordingly rather than applying a single template.
Serving Glendale, CA - Our Local Coverage Area
We’re based in the Glendale 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 Glendale
Because unsealed return plenums and attic connections pull ash back into the HVAC loop after cleaning. The visible dust was removed, but the gaps remained. Duct sealing closes those entry points so the system only recirculates air from your conditioned space, not your attic or crawlspace. Call (361) 326-5060 for a camera inspection and written estimate.
Yes. We seal shared-stack dryer vents through cleanout ports and individual unit ductwork through access panels, staging equipment through windows or loading docks when street parking is restricted on canyon roads. The price is still flat and written before work starts. Call (361) 326-5060 to discuss your building’s access.
It stops the re-entrainment cycle. Sealing the return plenum, attic flex connections, and supply junctions means your HVAC system pulls air only from inside your home, not from ash-laden attic cavities or crawlspaces. After sealing, filtration works because the air being filtered is the air you’re breathing, not contaminated bypass air. Call (361) 326-5060 for an inspection.
Yes. We seal the junctions between individual unit vents and the main stack with fire-rated mastic, accessible through cleanout ports or removable panels. This stops lint migration between units and reduces fire risk. The work is priced per stack, not per unit, and written before we start. Call (361) 326-5060 for building-specific pricing.
Every three to five years for inspection, with immediate sealing after any major wildfire event that sends smoke through your area. The Santa Ana winds and thermal cycling in hillside Glendale accelerate seal degradation, so we recommend camera inspection every third year to catch disconnections before they pull ash or attic air. Call (361) 326-5060 to schedule.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Glendale and the greater Los Angeles area since 2004.




Before
After
Before
After
Before
After