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.
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AfterFast, Reliable Duct Sealing Across Covina
Duct sealing in Covina typically runs $800 – $2,400 for a whole-house seal, depending on whether we’re patching a few disconnected runs or resealing an entire 1950s ranch system from the air handler to every register boot. Most Covina jobs take a half day, and you’ll get a written price before we touch anything. Call (361) 326-5060 for a free estimate.
We’ve been working in Covina’s postwar ranch neighborhoods since 2004, and our crews know the local housing stock cold. The low-pitch attics off Cypress Street, the original flex runs in Charter Oak, the retrofitted systems up near Covina Hills – we’ve sealed ducts in all of them. Dispatch and scheduling are coordinated from our Los Angeles office, but the technicians who show up at your door live and work in the San Gabriel Valley, not driving in from two counties away.
What makes Covina different from West Covina or Glendora is right there in the geography. Covina sits downwind of the 57 and 10 freeway corridors, and when the Santa Ana winds kick up, your attic becomes a collection point for brake dust, tire particulate, and diesel soot that coastal neighbors simply don’t see in the same concentration. Combine that with attic temperatures that crack 100°F from June through September, and you’ve got a duct system that fails by thermal stress – not just age. That’s why local experience matters. A tech who doesn’t know Covina’s specific failure modes will seal what he can reach and miss the blown collar at the air handler that’s been dumping attic air into your bedroom for three summers.
Why Hollis Air Duct Cleaning Is Covina’s Preferred Duct Sealing Company
Our reputation in Covina was built on showing up inside the window and pricing in writing – no exceptions. The Garrison Standard requires it, and our 365-Day Done Right Promise backs it up. If a seal fails within a year, we come back and make it right at no charge, including a free second visit. That’s not a satisfaction guarantee; it’s a written contract on every job.
We don’t chase the lowest teaser price. Our Covina customers are homeowners who’ve already been burned by a coupon that turned into a $3,000 invoice once the van was in the driveway. Hollis operates differently: one flat price per system, agreed before work starts, no per-vent add-ons, no fogging upsells. Our technicians are background-checked, uniformed, and accountable – you know who’s walking into your home before they arrive.
Phones are answered by a live person, 24 hours a day, seven days a week. No voicemail loops, no callback queues, no waiting until Monday to schedule. When you call (361) 326-5060, you talk to a human who can book your Covina appointment or answer questions about what duct sealing actually involves.
HVAC Duct Sealing in Covina
HVAC Duct Sealing in Covina is the process of closing leaks, reconnecting separated runs, and resealing register boots so that the air your system conditions actually reaches the rooms you live in – not your attic. In Covina’s 1950s-70s ranch tract homes, we routinely find that 20 – 30% of conditioned air is leaking into the attic through cracked mastic, brittle flex insulation, and disconnected collars. That’s air you paid to cool, heating your insulation instead of your bedroom.
A typical whole-house duct seal in Covina runs $800 – $2,400. Partial sealing of specific problem zones – a disconnected flex run, a blown air-handler collar, a cluster of failed register boots – usually falls in the $350 – $800 range. We price by the system, not by the vent, and we write it down before we start.
When Covina Homes Need Sealing, Not Just Cleaning
Cleaning removes debris from inside the duct. Sealing fixes the envelope so debris stops entering. In Covina, we see homeowners who’ve had their ducts cleaned twice in three years and still smell that dusty attic odor when the AC kicks on. The problem isn’t dirty ducts; it’s leaky ducts pulling attic air in through gaps the cleaning brush never reached. If your registers blow dust immediately after a cleaning, you need sealing.
What the Job Actually Involves
We pressurize the system and use smoke pencils or theatrical fog to locate leaks, then seal with mastic and fiberglass mesh – not duct tape, not caulk. Mastic remains flexible through 100°F+ attic cycles. We check the return plenum, filter slot, and air-handler collar, because return-side leaks in Covina pull Santa Ana wind grit straight into your blower motor. The work takes 3 – 6 hours for a typical ranch home.
Duct Repair in Covina
Duct Repair in Covina addresses physical damage that sealing alone won’t fix: crushed flex runs, rodent-chewed insulation, rusted sheet-metal boots, and completely separated collars. In Covina’s older ranches, we often find flex duct that was original to the 1962 build, with insulation that crumbles at touch and a vapor barrier that’s turned to powder. Sealing over that is pointless; the duct needs replacement.
Duct repair in Covina typically costs $400 – $1,200 for localized fixes – a section of flex replacement, a new register boot, a patched plenum. Extensive replacement of multiple runs in a whole-house system can reach $2,000 – $4,500. We always inspect with a camera first so you’re paying for what you actually need, not what we hope to sell.
Crushed and Disconnected Runs
Covina’s low-pitch attics leave little room to move, and decades of HVAC technicians stepping between joists have crushed flex runs flat or kicked collars loose. A crushed duct doesn’t just leak; it chokes airflow to the room it serves. We replace the damaged section with new insulated flex, properly supported and sealed, and we leave the attic path clear for future access.
Register Boot and Floor-Plate Failures
The metal boot where your floor or wall register meets the duct is a common failure point in Covina’s slab-on-grade ranches. The gasket dries out, the boot pulls away from the duct, and you get a direct leak into the wall cavity or under the slab. We reseat boots with mechanical fasteners and mastic, not hope and caulk.
Trusted Brands We Service in Covina
Our Covina crews carry professional-grade equipment from Rotobrush and Abatement Technologies, and we stock filtration and sealing products from Aprilaire and Guardsman. That means when we find a failed component in your Covina home, we don’t have to order parts and make you wait. We carry the mastic, mesh, collars, and boots that match Covina’s common duct sizes, so most repairs finish same day. The tools are commercial grade, not hardware-store gear, and we explain what we’re using and why – no black-box technician secrets.
Common Duct Sealing Problems We See in Covina Homes
- Thermal failure of mastic and flex in 100°F+ attics. Covina’s summer attic temperatures bake duct sealants until they crack and powder. We remove the old brittle material and apply fresh mastic rated for continuous high-heat exposure, then verify with a pressure test.
- Disconnected flex runs at air-handler collars. The vibration of modern high-efficiency blowers works collars loose over time, especially on original 1960s duct layouts that weren’t designed for today’s airflow rates. We reconnect with mechanical fasteners plus mastic, not just tape.
- Return-side leaks pulling Santa Ana wind grit into the system. Unsealed return plenums and filter slots act as vacuum cleaners for fine dust and wildfire ash during fall wind events. We seal the return path so your filter actually filters, not just decorates.
- Failed register boot gaskets in slab-on-grade ranches. The boots under your floor registers have been expanding and contracting through 60+ years of Covina heating seasons. When the gasket fails, you’re conditioning the space under your slab. We reseat and seal every boot we can access.
Pricing for Duct Sealing in Covina, CA
A typical whole-house duct sealing in Covina runs $800 – $2,400. Partial sealing of specific problem zones costs $350 – $800. Duct repair, when sections need replacement rather than sealing, ranges $400 – $1,200 for localized work and $2,000 – $4,500 for extensive replacement. These are real numbers for the Covina market, not teaser prices that jump once we’re inside.
What moves the price: accessibility of your attic, the extent of thermal damage to existing seals, whether we’re sealing or replacing sections, and how many register boots need reseating. We inspect with a camera before we quote, so the price we write down is the price you pay. No per-vent add-ons, no fogging upsells, no surprises at the door.
Estimates are free. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Covina
Our crews work throughout the San Gabriel Valley, including Duct Sealing in Covina and surrounding cities: Azusa, West Covina, Baldwin Park, and Glendora. Each area has its own duct failure patterns – Glendora’s hillside homes see different pressure differentials than Covina’s valley ranches – and our Duct Sealing teams are trained to recognize the difference.
Serving Covina, CA - Our Local Coverage Area
We’re based in the Covina 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 Covina
Yes, when the smell is caused by attic air leaking into the duct system through gaps at the air handler, disconnected flex runs, or failed register boots. We were called to a ranch home near Cypress Street in Covina where the homeowner complained of exactly this odor every time the AC kicked on. Camera inspection showed a disconnected flex run and a blown-out mastic seal at the air handler collar, leaking attic air straight into the system. We reconnected and sealed the run with mastic and mesh, then sealed the floor-register boots that had lost their gaskets, and the odor was gone on the next cooling cycle. If your ducts are clean but the smell persists, you likely need sealing, not another cleaning. Call (361) 326-5060 for a free inspection.
Covina’s combination of superheated attics, 1950s-70s ranch duct layouts, and wind-blown San Gabriel Valley grit creates thermal failures that coastal homes don’t experience at the same rate. Attic temperatures here crack 100°F for months each summer, drying mastic and cracking flex insulation, while the Santa Ana winds deposit fine dust and ash that enters through every gap. Coastal homes deal with moisture; Covina homes deal with heat cycling and particulate intrusion. The failure mode is different, and the repair approach is too. Call (361) 326-5060 to discuss your specific system.
No, not if it’s offered as a substitute for proper sealing or applied without first removing debris via negative-pressure source removal. Sealing over wet or contaminated duct interiors traps moisture under mastic, which feeds microbial growth in the flex insulation. A fogging chemical doesn’t fix a disconnected collar or cracked mastic seal, and in Covina’s hot attics, that moisture gets baked into the duct lining. Pay for mechanical sealing of actual leaks, not chemical theater. If you’re concerned about biological growth, we can inspect with a camera and recommend appropriate remediation – but we won’t sell you fogging as a fix for structural leaks. Call (361) 326-5060 for an honest assessment.
We pressurize the duct system and use smoke pencils, theatrical fog, or digital manometers to locate leaks precisely. For buried runs in Covina’s low-pitch attics, we feed inspection cameras through the ductwork to find disconnected collars, crushed sections, and failed boots without removing insulation or drywall. The camera also lets us show you the damage before we quote, so you know what you’re paying for. Most Covina attics have enough access to inspect the full system; when they don’t, we work from the register openings and the air handler. Call (361) 326-5060 to schedule a camera inspection.
Yes, but only if the sealing addresses the return side of the system, not just the supply. Covina’s Santa Ana wind events drive fine ash and brake dust into attic spaces, and an unsealed return plenum or filter slot pulls that grit straight into your air handler and blower motor. Sealing the supply ducts helps conditioned air reach your rooms, but sealing the return path is what keeps windblown particulate out of the system in the first place. We inspect and seal both sides. Call (361) 326-5060 for an estimate.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Covina since 2004.