Duct Sealing in Pasadena - Leakage Measured, Then Priced in Writing

Trusted Duct Sealing for Pasadena Homeowners

Duct Sealing - Pasadena means finding and closing the gaps, cracks, and loose connections in your HVAC ductwork that let conditioned air escape into attics, crawl spaces, and wall cavities. Most homes in Pasadena’s older neighborhoods, from Bungalow Heaven to the Craftsman districts south of the 210, lose 20 to 30 percent of the air they pay to heat and cool through leaky ducts. That’s real money leaving through gaps you can’t see. Hollis Air Duct Pasadena has been sealing ducts since 2004 under The Garrison Standard: written price before we touch anything, background-checked and uniformed techs on-site, and a 365-Day Done Right Promise in writing on every job. If the work fails within a year, we come back and make it right at no charge. Call (626) 469-5477 for a straight answer and a written quote.

Call (626) 469-5477

Duct Insulation

Duct Insulation is the barrier wrapped around your ductwork that keeps conditioned air at the right temperature as it travels from your furnace or AC unit to the rooms you actually live in. In Pasadena and nearby Duct Sealing - San Gabriel areas, where summer attic temperatures routinely exceed 140 degrees, uninsulated or poorly insulated ducts mean your air conditioner works harder than it should, and rooms at the end of long runs never quite reach the temperature on the thermostat. We inspect the insulation on every duct sealing job and replace sections that have been damaged by rodents, moisture, or age, typically running $300 to $800 for partial replacement on an average single-family Pasadena home. Full re-insulation of an entire system usually lands between $1,200 and $3,500, depending on how much of the ductwork runs through unconditioned space.

What Good Insulation Does

Proper duct insulation keeps cooled air cool and heated air warm while it’s in transit, which means your system doesn’t run extra cycles to compensate for temperature loss through the duct walls themselves. In Pasadena’s older homes, where ducts often run through uninsulated attics, this single upgrade can cut the temperature difference between the first and second floor by several degrees. We check insulation integrity with every sealing job and report what we find before recommending any work.

When Insulation Needs Replacement

Rodents nesting in Pasadena attics, from Altadena Duct Sealing territory to Hastings Ranch, chew through fiberglass duct wrap and leave it compressed, torn, or soiled. Water intrusion from roof leaks or condensation does the same damage more slowly, and any insulation that’s been wet loses most of its R-value permanently. If the wrap is sagging, stained, or missing in sections, the right repair is replacement, not a patch over the top.

HVAC Duct Sealing

HVAC Duct Sealing is the process of closing every leak point in your heating and cooling distribution system so the air your equipment produces actually reaches your rooms instead of bleeding into the attic or crawl space. Pasadena homes built before the 1990s often have ducts joined with foil tape that dries out and fails over time, and the joints where duct sections meet the main trunk line are the most common leak points we find. Hollis Air Duct Pasadena uses mastic sealant, the same material specified by commercial HVAC codes, applied at every accessible joint and connection, with whole-home sealing typically priced at $800 to $2,500 depending on system size and accessibility. We follow the negative-air method where practical, which means sealing the registers, pressurizing the duct system, and measuring the actual leakage before and after the work with a duct blaster.

Where Ducts Actually Leak

The biggest leaks are rarely in the long straight sections. We find most of the air loss at the boots where registers connect to the duct, at the plenum where the main trunk meets the air handler, and at every Y or T fitting in between. These are also the spots where dust gets pulled back into your system when the blower cycles on, which means sealing them improves the air moving through your home, not just your energy bill.

Testing Before and After

On larger systems or when a homeowner wants proof, we run a duct leakage test that pressurizes the system and measures how much air escapes in cubic feet per minute. The before number shows you what you’re losing; the after number shows what we fixed. It’s the difference between a crew that tells you they did a good job and one that can prove it with a gauge.

Duct Repair

Duct Repair addresses the physical damage that prevents your system from moving air at all: disconnected sections, crushed flex ducts, holes gnawed by rodents, and sections that have collapsed under attic debris or poor original installation. Pasadena’s older housing stock, especially in neighborhoods like Madison Heights and Catalina Villas, plus nearby Alhambra Duct Sealing areas, has plenty of ductwork that was installed decades ago and never touched since. We repair what can be repaired and replace what can’t, with simple repairs like reconnecting a fallen section or patching a small hole running $150 to $450, while full section replacements and major structural repairs typically fall between $600 and $2,000. Every repair is covered in writing by the 365-Day Done Right Promise, and if it fails within a year, we return and fix it at no charge.

Signs of Physical Duct Damage

Rooms that never reach temperature no matter how long the system runs are often a sign of a disconnected or crushed duct, not an undersized AC. If you notice one specific room or zone that’s always ten degrees off from the rest of the house, there’s usually a physical problem in the duct run feeding that space. We find disconnected ducts in crawl spaces and attics in Pasadena weekly, often from original installation work that never quite fit together right.

Why Rodent Damage Happens

Pasadena’s foothill neighborhoods, from Annandale to Linda Vista, back up to open space that keeps a healthy population of roof rats and squirrels moving through residential areas. Flexible ductwork is warm in winter and cool in summer, which makes it attractive nesting material, and a rat can chew through a flex duct in a single night. Repairing rodent damage means sealing the entry points into your attic as well as the ducts themselves, or you’ll be calling us back next season for the same fix.

Air Duct Sealing

Air Duct Sealing is the specific job of finding and closing air leaks in your ductwork using mastic, foil tape rated for HVAC use, and mechanical fasteners where connections have worked loose. It’s not the same as cleaning, though the two jobs work well together: sealing after a cleaning means you’re locking out dust, not locking it in. In Pasadena, where summer temperatures push AC systems hard from June through October, the payback on properly sealed ducts often shows up in the first year of utility bills. Whole-home air duct sealing runs $800 to $2,500 for a typical single-family Pasadena house, with simpler jobs sealing just the accessible main trunk and register boots priced from $450 to $800.

Mastic vs. Tape

We use mastic sealant, a thick paste that dries hard and never peels, on every joint we can reach. Hardware-store foil tape, the kind with the peel-off backing, dries out and fails in attic heat within a few seasons, which is why you see so much of it hanging loose in older Pasadena homes. Mastic doesn’t shrink, doesn’t dry out, and it’s what code requires on new commercial installations.

Sealing After Cleaning

The best time to seal ducts is right after a proper cleaning, when the interior surfaces are free of the dust and debris that would otherwise get trapped behind new sealant. If your ducts have never been cleaned and the system is older, we may recommend a cleaning first, then sealing, to make sure the work lasts. Check our home page for more on how cleaning and sealing work together, or ask the technician when you call.

Duct Sealing Services

Duct Sealing Services at Hollis Air Duct Pasadena are the full-scope job: inspection, leakage testing where appropriate, sealing every accessible joint and connection, and a written report of what we found and what we did. We don’t do partial jobs that leave half your system leaking, and we don’t quote a low teaser price that balloons once the truck is in your driveway. The price for full duct sealing services on a typical Pasadena home runs $800 to $2,500, written down before any work starts, and it doesn’t move at the door. If you only need the accessible trunk line and register boots done, expect $450 to $800.

What’s Included in the Quote

Every quote includes a walkthrough of your attic or crawl space access points, a visual inspection of accessible ductwork, and a clear list of what we’ll seal, what we recommend replacing, and what it costs. Nothing gets added on site without your written approval first, and if the technician finds something unexpected, they’ll show you photos and explain the options before touching it. That’s The Garrison Standard, and it’s the same standard our related Duct Sealing in Glendale crews operate under.

Why the Price Ranges Exist

Duct systems vary widely in Pasadena depending on the age of the house, the number of runs, and how much of the ductwork is accessible. A 1940s bungalow with a single trunk line and six registers is a different job than a 1990s two-story with dual zones and ducts buried in hard-to-reach spaces. We price each job on what we can see and measure, which is why the written quote matters more than any range on a website.

Brands We Service

We work on duct systems connected to every major HVAC brand installed in Pasadena over the past four decades, and we carry materials compatible with all of them. Rotobrush equipment is part of our toolkit for cleaning ducts before sealing, and we routinely use negative-air machines from Nikro and Abatement Technologies to capture dust and debris during the job rather than letting it drift back into your living space. Filtration products from Aprilaire, Honeywell, and Guardsman are what we recommend when a sealing job reveals that your existing filter setup isn’t doing enough for the air in your home.

Whether your system is a builder-grade unit from the 1990s or a newer high-efficiency heat pump, the ductwork is where the real losses happen. We service all makes and models of HVAC equipment connected to the duct systems we seal. If you’re in Downtown Los Angeles and working with an older building’s duct infrastructure, our partners there deal with the same leak patterns we see in Pasadena’s mid-century construction.

Signs You Need a Pro Right Now

• Rooms that never reach temperature. If one bedroom is always ten degrees off from the thermostat setting, you’re likely losing conditioned air through leaks or a disconnected section before it reaches that register. The system runs longer to compensate, which shortens equipment life and raises utility bills month after month.
• Visible dust around registers. When ducts leak, the pressure difference pulls attic and crawl space air back into the system through the gaps, and that air carries dust, insulation fibers, and whatever else is floating around up there. Dark streaks or dust buildup around supply registers is a classic sign of return-side leakage.
• Utility bills climbing without explanation. If you’re paying more to heat and cool your Pasadena home than you were three years ago and your equipment is well-maintained, leaky ducts are a prime suspect. Twenty to thirty percent air loss is normal in unsealed older systems, and sealing it back is a permanent fix, not a seasonal adjustment.
• Hot or cold spots between adjacent rooms. Two rooms on the same zone with the same thermostat reading completely different temperatures usually means the duct run to one of them is leaking or partially disconnected. The fix is a targeted repair, not a bigger AC unit.
• You hear air moving where it shouldn’t. A faint whistle or hiss from a wall cavity or attic space when the blower kicks on means air is escaping through a gap somewhere in the duct path. That’s conditioned air you paid for, bleeding into space you don’t use.

Our Process, Step by Step

1. 1
   Inspection and scope. We walk the accessible ductwork in your attic, crawl space, or utility closet and look for the obvious problems first: disconnected sections, crushed flex, torn insulation, and joints that have separated. We note the accessibility of every section so the quote reflects what we can actually reach and seal.
2. 2
   Written quote before work starts. You get a price on paper that covers the full scope we discussed, and it doesn’t change once the work begins. If we find something unexpected that needs attention, we stop, show you what we found, and get your written approval before adding anything.
3. 3
   Prep and protection. We cover the work area with drop cloths when accessing ducts from interior spaces, and we wear shoe covers through your home. The goal is to leave your house the way we found it, minus the leaks.
4. 4
   Sealing and repair. Every accessible joint, boot connection, and fitting gets mastic sealant or properly rated HVAC foil tape where mechanical fastening is needed. We replace sections that are too damaged to seal, and we re-insulate anything we had to open up. On larger jobs we run a duct leakage test before and after so you can see the improvement in measured numbers.
5. 5
   Walkthrough and documentation. Before we leave, we walk you through what we did, show you photos of the before and after where it matters, and hand you the written 365-Day Done Right Promise. If anything fails within a year, we come back and fix it at no charge, including a free second visit.

How Much Does Duct Sealing Cost in Pasadena?

Our Service Area Near Pasadena

Hollis Air Duct Pasadena serves the city proper along with the surrounding San Gabriel Valley communities, including Duct Sealing in Pasadena job sites from Altadena down through South Pasadena. We regularly work in Glendale, Burbank, Arcadia, Monrovia, El Monte, Alhambra, Highland Park, Montebello, Pico Rivera, and East Los Angeles, with most appointments scheduled inside a two-hour window. If you’re checking whether a leaky duct system is worth fixing or watching pages like our Duct Sealing in Pasadena guide, the quickest way to a straight answer is a phone call.

Frequently Asked Questions About Duct Sealing in Pasadena

Schedule Your Duct Sealing Service in Pasadena Today

If you suspect your ducts are leaking, the next step is a phone call to (626) 469-5477. We’ll walk you through what we’d look at, give you a straight answer on cost, and schedule a free estimate with a written quote before any work starts. The 365-Day Done Right Promise backs every job in writing, and a live person answers the phone 24/7. No pressure, no moving targets, just a squared-away crew and a price that holds.

Written by Roy Castellanos, Owner at Hollis Air Duct Pasadena, serving Pasadena since 2004.