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

Fast, Reliable Duct Sealing Across Alhambra

Duct sealing in Alhambra typically runs $900 – $2,400 per system depending on access and how much of the ductwork needs mastic and reinforcement. Most jobs in the city’s older homes take one day once we map the runs. If you’re losing conditioned air into attics or wall cavities, or if Santa Ana dust keeps showing up on your registers, call (626) 469-5477 for an honest assessment and a written price before any work starts.

Call (626) 469-5477

We know Alhambra’s housing stock. We know the converted gravity systems in Emery Park and the Bean Tract, the stucco crawlspaces, and the patchwork ductwork from decades of additions. That local knowledge changes how we approach every job, because sealing ducts in a 1927 Spanish Colonial Revival is not the same as sealing ducts in a 1990s tract house.

Why Hollis Air Duct Pasadena Is Alhambra’s Preferred Duct Sealing Company

Our Duct Sealing crews work in Alhambra weekly. Homeowners here call us after other companies miss leaks, or after a cheap quote ballooned at the door. We write the price before we touch anything. That’s The Garrison Standard, and it’s how we’ve done business since 2004.

Every technician who arrives in Alhambra is background-checked and uniformed. They arrive inside the quoted window. They explain what they found before sealing anything. And the work is covered by our 365-Day Done Right Promise: if a sealed joint fails within a year, we come back and make it right at no charge. That includes a free second visit, not a negotiated callback.

Roy Castellanos leads our crews with a simple rule from The Garrison Code: do the job by the book, show the homeowner what you found, and leave the site cleaner than you found it. In Alhambra, where homeowners have been burned by no-shows and price jumps, that discipline matters.

Duct Insulation in Alhambra

Duct insulation in Alhambra matters because attics here bake in summer, and unconditioned ducts running through 130-degree attic spaces lose cooling before it reaches the bedroom. For the city’s older homes with long, snaking runs through crawlspaces and add-on rooms, proper insulation keeps the air you paid to condition at the temperature it should be.

We see two situations most often. First, older fiberglass wrap that has deteriorated, torn, or been pulled apart during remodels. Second, ducts that were never insulated to begin with because the original gravity system didn’t require it. In both cases, we remove the old material, inspect the duct surface, and install new insulation with a proper vapor barrier.

When Older Wrap Fails

In Alhambra’s Spanish Colonial and Craftsman homes, original duct wrap often dates back decades. It degrades. Rodents nest in it. Remodel crews tear it during additions and never replace it. A torn section along a 30-foot attic run can lose 20-30% of cooling capacity at the far end of the house.

Insulation for Converted Systems

Gravity-to-forced-air conversions often left active ducts running through unconditioned spaces with nothing between the metal and the attic air. Insulating those runs is the difference between a bedroom that cools in 15 minutes and one that never quite gets comfortable in August.

Most duct insulation jobs in Alhambra run $600 – $1,800 depending on run length and access. We include it in the written quote when the inspection shows heat loss is happening.

HVAC Duct Sealing in Alhambra

HVAC duct sealing in Alhambra addresses the leaks and failed joints that let conditioned air escape into attics, walls, and crawlspaces. Ducts in the city’s older homes were rarely sealed well even when new, and fifty or more years of temperature swings have separated joints and cracked old tape.

We apply mastic to every accessible joint, seam, and connection. Mastic is not tape. It is a brush-on sealant that hardens into a flexible, permanent bond. On accessible duct systems, we also inspect for disconnected sections and abandoned branches. The goal is simple: air leaves the air handler and arrives at the register, not in a wall cavity.

Mastic Sealing on Accessible Ducts

Where ductwork is exposed in attics and crawlspaces, we can seal it thoroughly. We clean the surface, brush mastic onto every seam, and reinforce loose connections. This is the single biggest efficiency gain most Alhambra homeowners can make without replacing ductwork.

Camera Verification Before and After

Because most of what we do is hidden, we run a camera inspection before sealing and after. Homeowners see the gaps, the dust, and the finished work. If there’s an abandoned branch pulling dust from a wall cavity, the camera finds it. That documentation is part of every job, not an upsell.

HVAC duct sealing in Alhambra typically runs $850 – $2,200 per system. Homes with multiple systems or hard-to-access ductwork land on the higher end. There are no per-vent prices and no surprise line items. The written quote is the price.

Trusted Brands We Service in Alhambra

We work on all major residential equipment and duct systems in Alhambra, and we stock the consumables needed for the most common installations in the area. That includes filtration products from Aprilaire and Guardsman for homes where sealing reveals compromised air quality, and we’re equipped with Rotobrush and Abatement Technologies inspection tools to see inside ductwork before and after we seal it. If your system uses standard flex or rigid metal ducting, we have what we need to get the job done without a second trip.

Common Duct Sealing Problems We See in Alhambra Homes

• Abandoned gravity-heating branches left uncapped. In homes where gravity heat was converted to forced air, old ducts often remain connected to wall cavities or floor spaces. They keep collecting dust and redistribute it every time the system runs. We trace and cap these during sealing jobs.
• Leaky joints causing your air handler to work harder. Santa Ana winds push fine dust into attic spaces, and a leaky return pulls that dust straight through gaps in the ductwork. Sealing those returns stops the dust at the source instead of just filtering it out.
• Shifted or separated runs behind walls and floors. Alhambra’s Spanish Colonial and Craftsman homes have settled for 70 to 100 years, and duct sections shift with the framing. Joints separate slowly, and you won’t notice until a room stops cooling or heating evenly.
• Incompatible duct materials from multiple additions. A 1930s original metal trunk line feeding a 1980s flex run to a 1990s addition means different connection types, different seal requirements, and easy places for leaks to form. Each joint needs a specific sealing method.

Pricing for Duct Sealing in Alhambra, CA

We Also Serve Cities Near Alhambra

In addition to our work throughout Alhambra, our crews regularly serve San Gabriel, Rosemead, Pasadena, and Temple City. If you’re in one of those neighborhoods and dealing with the same aging ductwork and Santa Ana dust, call us. We schedule Alhambra-area work together when we can to keep trip times short.

FAQs About Duct Sealing in Alhambra