Duct Sealing in Alhambra - Tested First, Written Price Second

Fast, Reliable Duct Sealing Across Alhambra

Duct sealing in Alhambra typically costs $800 – $2,400 for a whole-home system, depending on accessibility and the condition of the original ductwork. Most jobs are completed in a single day, and we always provide a written price before any work begins. Call us at (361) 326-5060 for a free estimate.

Call (361) 326-5060

We know Alhambra’s housing stock because we’ve worked inside it. Our crews serve Alhambra from our Los Angeles metro office, and we’ve sealed ducts in the ranch tracts near Almansor Park, the apartment buildings along Valley Boulevard, and the mid-century homes south of Main Street. These houses were built between 1945 and 1970 with galvanized steel ductwork that was never designed to last this long. Joints leak. Branch runs disconnect under attic insulation. Return-air plenums were often skipped entirely. The result is the same: your HVAC works harder, your bills climb, and attic dust keeps circulating. We find the leaks, seal them with mastic and mesh, and leave you with a system that moves air the way it was supposed to.

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

Hollis Air Duct Cleaning has been part of the Garrison Partners family since 2004. That track record matters in Alhambra, where homeowners have seen plenty of fly-by-night outfits promise cheap duct work and disappear. We’re still here because we do what we say we’ll do.

Our technicians are background-checked, uniformed, and trained to The Garrison Standard: arrive inside the quoted window, price the job in writing before touching anything, complete the work by the book, and leave the site clean. Every duct sealing job in Alhambra carries our 365-Day Done Right Promise. If the seal fails or the leak returns within a year, we come back and make it right at no charge, including a free second visit.

Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops. No callback queues. When you call (361) 326-5060, you talk to someone who can schedule your Alhambra appointment.

Duct Sealing Services in Alhambra

Duct Sealing Services in Alhambra address a problem most homeowners don’t know they have: conditioned air escaping through gaps, disconnected joints, and deteriorated seals in the duct system. In a city where summers regularly hit 95°F and the San Gabriel Valley smog belt pushes fine particulates into every attic, leaky ducts don’t just waste money. They pull that contaminated attic air straight into your living space. A typical whole-home duct sealing job in Alhambra runs $800 – $2,400, with simpler single-zone repairs starting around $400. We price by the system, not by the vent, and we put that price in writing before any work starts.

Camera Inspection and Leak Detection

We don’t guess where your ducts are leaking. Our techs run a camera through the system first, especially in Alhambra’s older ranches where galvanized trunk lines hide under blown-in insulation. We’ve found completely disconnected branch runs, crushed flex duct, and joints that have been open for decades. The camera shows you what we see, and the inspection guides exactly where we apply mastic sealant and reinforcing mesh.

Mastic Sealing and Joint Reinforcement

Duct tape fails. We use water-based duct sealing mastic, brushed onto every joint and seam, then reinforced with fiberglass mesh where the trunk line flexes or where previous repairs have failed. In Alhambra’s 1960s apartment buildings with vertical chases, we often need to access ductwork through carefully cut access panels, seal the joints, and restore the chase walls. The work is permanent, not a patch.

Duct Insulation in Alhambra

Duct Insulation in Alhambra solves a different problem than sealing, though the two often go together. Original ductwork in 1945 – 1970 ranch homes was frequently installed with minimal or no insulation at all. In attics that reach 140°F during San Gabriel Valley heat waves, uninsulated supply ducts lose 20 – 30% of their cooling before the air ever reaches your vents. Duct insulation in Alhambra typically costs $1,200 – $3,000 for a full system, depending on linear footage and attic accessibility. We wrap sealed ducts with formaldehyde-free fiberglass insulation, secured and sealed at every seam, then jacket the runs for durability.

Attic Duct Insulation Replacement

Original insulation on Alhambra’s galvanized ducts has often crumbled to dust after 60+ years. We remove the degraded material, clean the metal surface, seal any newly exposed joints, and install fresh insulation rated for the temperature extremes of San Gabriel Valley attics. The difference in register temperature is immediate and measurable.

Apartment Vertical Chase Insulation

In 1960s – 80s apartment buildings along Valley Boulevard, centralized duct chases run through unconditioned wall cavities. These chases act as thermal bridges, baking in summer and condensing in winter. We insulate the ductwork within these chases using materials from Abatement Technologies and Guardsman that meet California fire-safety codes for multi-family construction.

Trusted Brands We Service in Alhambra

We stock parts and materials from Aprilaire, Abatement Technologies, and Guardsman for Alhambra jobs, which means faster turnaround and no waiting on shipping for standard repairs. Our equipment roster also includes Rotobrush rotary brush systems and Nikro negative-air machines for the cleaning work that often precedes sealing. When we find a failed component during a duct sealing job, we replace it with the same-grade material, not a hardware-store substitute. For filtration upgrades after sealing, we source Honeywell and Aprilaire media filters sized to your system’s new airflow profile.

Common Duct Sealing Problems We See in Alhambra Homes

• Disconnected galvanized trunk joints under attic insulation. In Alhambra’s 1950s ranches, the original duct installer often buried joints under a thin layer of insulation that has since compressed. The joints worked loose decades ago. Without a camera inspection, you’d never know half your conditioned air is heating your attic.
• Missing return-air plenums pulling attic dust and smog. Many Alhambra tract homes were built with the return duct drawing directly from a joist bay or wall cavity, with no sealed plenum box. The system recirculates whatever is in that space: attic dust, San Gabriel Valley smog particulates, pollen from the heavy tree canopy. Sealing the supply side alone doesn’t fix this.
• Crushed or kinked branch runs in original construction. On a 1953 ranch off South Almansor Street, our tech ran a camera inspection and found a crushed 6-inch branch run feeding two bedrooms, plus half the joints on the galvanized trunk disconnected under attic insulation. We pulled the system under negative pressure with HEPA filtration, sealed the trunk joints and the branch with mastic and mesh, and rebalanced supply and return ducts – airflow at the far registers came back and the recurring dust smell at the air handler stopped.
• Oversized sealing in apartment vertical chases starving upper-floor registers. In 1960s – 80s apartment buildings along Valley Boulevard, the original ductwork was often undersized for the building’s load. Aggressive sealing without airflow testing can reduce already-marginal supply to top-floor units. We measure static pressure and register flow before and after sealing to prevent this.

Pricing for Duct Sealing in Alhambra, CA

We Also Serve Cities Near Alhambra

Our crews work throughout the San Gabriel Valley, including Alhambra and the surrounding communities of South Pasadena, San Marino, Monterey Park, and San Gabriel. Scheduling and dispatch are coordinated from our Los Angeles metro office, with local crews serving each area. If you’re in one of these neighboring cities and need Duct Sealing, the same pricing structure and 365-Day Done Right Promise apply.

FAQs About Duct Sealing in Alhambra