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.
Before
After
Before
After
Before
AfterFast, Reliable Duct Sealing Across San Dimas
Duct sealing in San Dimas typically runs $450 – $1,200 for a whole-home scope, depending on whether we’re sealing accessible joints on original 1960s – 80s ductwork or repairing crushed and disconnected runs found during camera inspection. Most San Dimas jobs are scheduled within a few days and completed in a single visit. If you’re in the flatland tracts off Arrow Highway or up in the Via Verde foothill pockets, our crew dispatches from the Los Angeles office and arrives inside the quoted window, uniformed and background-checked, with the price written down before any work starts. Call (361) 326-5060 for a free estimate.
We’ve worked on enough San Dimas homes to know the pattern: original galvanized trunk lines sweating at the seams, flexible branch runs crushed by decades of attic traffic, and boots that were never properly sealed when the house was built. The dry desert winds and spring pollen loads here don’t create the problem overnight, but they make the leaks impossible to ignore once the airflow drops and the energy bill climbs. Our Duct Sealing team treats every job as a diagnostic first, repair second, seal last. That’s The Garrison Standard.
Why Hollis Air Duct Cleaning Is San Dimas’s Preferred Duct Sealing Company
Hollis Air Duct Cleaning has been part of the Garrison Partners family since 2004, and our reputation in San Dimas is built on showing up when we said we would and pricing the job before we touch it. Homeowners here aren’t looking for the lowest teaser quote; they’re looking for the quote that doesn’t change at the door. We write the price down. It doesn’t move.
Our technicians are background-checked, uniformed, and accountable. You know who’s walking into your home before they arrive. And if the work fails within a year, we come back at no charge. That’s the 365-Day Done Right Promise, backed in writing on every job, not negotiated after the fact.
Dispatch and scheduling for San Dimas are coordinated from our Los Angeles office, but the crews serving your neighborhood are local. They know the difference between a 1968 flatland tract off San Dimas Avenue and a custom foothill build on Via Verde. That local knowledge matters when the ductwork you’re sealing was installed before modern mastic standards existed.
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 get on the schedule.
HVAC Duct Sealing in San Dimas
HVAC Duct Sealing in San Dimas means addressing the original galvanized trunk lines and early flexible branch runs that dominate the local housing stock, most of which were installed with minimal or no sealing at the boots and plenum connections. The job involves camera inspection first, then source removal of accumulated debris, then sealing accessible joints with mastic and mesh or foil-backed tape rated for thermal cycling. A typical sealing scope in San Dimas runs $450 – $850 for a single-system home with accessible attic ductwork; multi-zone systems or homes requiring significant repair before sealing can reach $1,000 – $1,200.
Camera Inspection Before Sealing
We don’t seal what we haven’t seen. Our techs run a camera through the return and supply trunks to locate open seams, disconnected boots, and crushed flexible runs. In San Dimas, this step often reveals that the real problem isn’t minor leakage at accessible joints; it’s a galvanized trunk sweating at the seams or a branch run flattened by a cable installer twenty years ago. Sealing without this inspection wastes your money and traps debris in a tighter system.
Source Removal and Filtration
Before we seal, we set the system under negative pressure with HEPA filtration and remove accumulated dust, pollen, and trail debris from the accessible runs and plenum. San Dimas’s spring pollen loads and Santa Ana ash events deposit fine material at the air handler and blower motor. Sealing over that debris just traps it. We remove it first, then seal, so the system moves cleaner air through tighter ductwork.
Duct Repair in San Dimas
Duct Repair in San Dimas is often the necessary predecessor to effective sealing, because original flexible branch runs from the 1970s and 1980s have frequently been crushed, disconnected at the boot, or damaged by pest activity in attics and crawlspaces. Repair work ranges from reconnecting and supporting a crushed branch run to replacing sections of deteriorated flexible duct or repairing open plenum connections. Typical duct repair in San Dimas runs $300 – $700 for isolated branch-run work; extensive trunk-line repair or multi-zone reconfiguration can reach $800 – $1,500 before sealing begins.
Crushed and Disconnected Runs
This is the most common find in San Dimas attics. A flexible branch run gets stepped on during a solar panel install or cable pull, or the support strap fails and the run sags onto the attic insulation, kinking flat. No amount of top-side sealing fixes zero airflow. We reconnect, replace, or reroute the run, then seal the new connection properly.
Galvanized Trunk Restoration
Original galvanized steel trunks in San Dimas flatland homes often show seam separation after forty-plus years of thermal expansion and contraction. We repair accessible seams with mastic and mesh, or recommend partial replacement when corrosion is advanced. This is structural repair, not cosmetic sealing, and it has to be done right or the leakage returns within a season.
Trusted Brands We Service in San Dimas
Our equipment roster includes Rotobrush rotary brush systems for mechanical agitation, Nikro negative-air machines for controlled debris extraction, and filtration products from Honeywell and Aprilaire for homeowners who want upgraded protection after sealing. We don’t show up with hardware-store shop vacs and duct tape. For San Dimas customers, this means we can source the right fittings, boots, and mastic products for original ductwork configurations that big-box stores don’t stock, and our turnaround on parts keeps your job on schedule instead of stretching across multiple visits.
Common Duct Sealing Problems We See in San Dimas Homes
- Original galvanized trunk seams opening under thermal cycling. The 1960s – 80s flatland tracts in San Dimas were built with galvanized steel trunks that expand and contract twice a day, every day, for decades. The longitudinal seams open slowly, leaking conditioned air into unconditioned attic space. Camera inspection finds the real loss path; surface sealing of visible joints misses it entirely.
- Flexible branch runs crushed during decades of attic work. Cable installers, solar crews, and pest control technicians have been in these attics over the years. A flexible branch run gets stepped on, kinked, or disconnected at the boot. The homeowner feels weak airflow in one room and assumes it’s a vent issue. It’s a duct repair issue, and sealing alone won’t restore airflow.
- Unsealed boots and plenum connections from original construction. When these homes were built, sealing standards were minimal or nonexistent. The flexible branch connects to the boot with a zip tie or friction fit, leaking into the attic or crawlspace for forty years. We seal these connections with mastic and mesh, properly supported, so they hold through the next thermal cycle.
- Fine ash and pollen accumulation at the air handler after wind events. Santa Ana winds and spring desert winds push debris through outdoor intakes and any existing leaks. The material collects at the blower motor and evaporator coil. Sealing without source removal traps this debris in a now-tighter system, reducing efficiency and potentially affecting indoor air quality.
Pricing for Duct Sealing in San Dimas, CA
Whole-home duct sealing in San Dimas typically costs $450 – $850 for a single-zone system with accessible attic ductwork and no significant repair needs. Homes requiring duct repair before sealing, or multi-zone systems in the foothills, generally fall in the $800 – $1,200 range. What moves the price: the amount of accessible ductwork, the condition of original materials, whether camera inspection reveals crushed or disconnected runs requiring repair, and whether the air handler and blower compartment need sealing as part of the scope.
We give one flat price per system, agreed in writing before work starts. No per-vent pricing. No add-ons at the door. You’ll see before-and-after photos of your own ducts, and you’ll know exactly what was sealed, repaired, or replaced. Estimates are free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near San Dimas
Our crews regularly work in San Dimas and the surrounding communities, including La Verne to the west, Glendora to the east, Covina to the south, and Azusa to the north. The same 1960s – 80s housing stock and foothill climate patterns extend across this corridor, and we bring the same diagnostic approach, written pricing, and 365-Day Done Right Promise to every job in the San Gabriel Valley.
Serving San Dimas, CA - Our Local Coverage Area
We’re based in the San Dimas 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 San Dimas
Original construction in San Dimas’s flatland tracts used galvanized steel trunks and early flexible branch runs with minimal or no sealing at the boots and plenum connections. Forty-plus years of thermal cycling has opened seams that modern ductwork, built to tighter standards, simply doesn’t have. A newer home starts sealed; these homes start leaky and get worse. Call (361) 326-5060 for a free camera inspection and written estimate.
Yes. Santa Ana wind events push fine ash and debris through outdoor HVAC intakes and any existing duct leaks, accelerating accumulation at the air handler and blower motor. After major wind events, we see a spike in calls from foothill neighborhoods where original ductwork has been pulling in outside air for decades. Sealing without source removal traps that debris; we remove it first, then seal. Call (361) 326-5060 to schedule after the winds pass.
Yes. Custom and infill homes in the Via Verde area often have multi-zone HVAC with more complex duct routing and smaller, harder-to-access plenum connections. We camera-inspect each zone, identify the specific leakage points, and write a scope that addresses the actual system configuration rather than applying a flat-rate template. Pricing reflects the additional access time and materials. Call (361) 326-5060 for a zone-by-zone assessment.
On a sealing call in the Via Verde foothill pocket, our tech camera-inspected the return and found the original galvanized trunk from the 1970s sweating at the seams and two crushed flexible branch runs feeding a rear bedroom. We set the system under negative pressure with HEPA filtration, performed source removal at the boots, and sealed the accessible runs and plenum with mastic and mesh – airflow at the far registers came back and the homeowner stopped smelling the trail dust that had been pulling in off the foothills. A generic sealing job would have missed the crushed runs and sealed over the debris.
We seal the accessible plenum connections, air handler cabinet seams, and blower compartment where leakage is found during inspection. In San Dimas, the blower compartment is often a significant leakage point because original installations didn’t include gasketed access panels. Sealing only the visible attic runs while ignoring the air handler is half a job. We price and perform the full accessible scope, and we show you the photos. Call (361) 326-5060 for a complete assessment.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving San Dimas and the San Gabriel Valley.