Duct Repair & Sealing Cost - Tested First, Written Price Second

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Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents

Worth knowing

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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Before & after – our own jobs

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How Much Does Duct Repair & Sealing Cost in Los Angeles?

Duct repair and sealing in Los Angeles typically runs $450 to $1,200 for most single-family homes, with simple joint-and-boot sealing on a smaller system landing near the low end and larger repairs involving crushed flex runs or disconnected trunks pushing past $1,500. If you’re sealing a whole attic system in a 1960s San Fernando Valley ranch house with 25 to 30 accessible runs, expect to land right in the middle of that range. We write the price down before any work starts, so the number you hear on the phone is the number you pay at the door.

That’s the short answer. The rest of this page is the long answer: what each job costs line by line, what pushes a Los Angeles home toward the top of the range, and how to tell whether you’re being quoted fairly. If you want a real number for your address instead of a range, call (361) 326-5060 and we’ll price it over the phone or send a technician out for a free estimate through our Duct Repair & Sealing in Los Angeles service.

Key Takeaways

• Most Los Angeles duct sealing jobs fall between $450 and $1,200; major repairs with new duct sections run $1,200 to $2,500.
• Attic and crawlspace ducts in older LA housing stock fail faster than anywhere else in the country because of heat cycling and seismic movement.
• The 365-Day Done Right Promise covers every repair in writing for a full year. If it fails, we come back at no charge.
• Prices are written before work begins and do not move once the technician is inside your home.

Duct Repair & Sealing Cost Breakdown (2026)

Here’s what the work actually costs in Los Angeles this year. These ranges cover labor and materials for a typical 1,800 to 2,400 square foot home. Yours may land higher or lower depending on how much of the system is reachable.

What drives cost up

Three things move the number the most: how much duct is reachable, how bad the existing leaks are, and whether the system needs new duct sections. A 1998-built home in Alhambra with an accessible attic and modern flex will cost less to seal than a 1948 bungalow in Highland Park with a hot, cramped, low-clearance attic where every run is stapled at a bad angle. Sealing alone is cheap; replacing crushed runs and correcting how the whole system hangs is where the money goes.

What drives cost down

Bundling. If you’re already having your ducts cleaned, sealing the joints right after costs less in labor because the crew is already on site with the negative-air machine set up. That’s one of the reasons we recommend scheduling the duct cleaning and sealing together rather than months apart. We also see lower totals when homeowners handle access themselves, clearing attic panels and crawlspace hatches before the technician arrives.

What Affects Duct Repair & Sealing Pricing in Los Angeles

• Housing age and construction type. LA has three distinct eras of ductwork: pre-1970 tract homes with original sheet metal, 1980s to 1990s condos with flex runs in tight chases, and post-2000 construction with tighter but less accessible chases. Each prices differently. Older sheet metal is often repairable but needs resealing at every joint; flex from the 90s is frequently crushed and best replaced.
• Attic and crawlspace accessibility. A San Fernando Valley ranch house with a tall attic allows a technician to move freely, which keeps labor hours down. A Silver Lake hillside home on piers, or a condo with a sealed interior chase, can double the time required to reach the same number of joints.
• Seismic and foundation movement. Southern California’s regular micro-seismic activity and expansive clay soil shift homes enough to separate duct joints over time. We see this in older Pasadena and Glendale neighborhoods where every seismic event nudges a joint loose. Reattaching and sealing those joints is routine work for us, and it’s the reason we recommend checking duct connections after any noticeable quake.
• Heat cycling and attic temperatures. Attic temps in the San Gabriel Valley and Van Nuys regularly exceed 140°F in summer. Flex duct outer jackets degrade in that heat, mastic dries out and cracks, and foil tape peels. That’s why the same duct installed in a cooler climate lasts longer than duct installed in a Los Angeles attic.
• Rodent and pest damage. In hillside neighborhoods like Hollywood Hills, Sherman Oaks, and the canyons, rats chew through flex duct for the warmth. Repair is not just patching a hole, it’s replacing the run and closing off the entry. Expect a per-run replacement cost.
• Number of runs and system size. A 1,200 square foot condo may have 8 runs. A 2,800 square foot two-story in Woodland Hills may have 26. Pricing scales with the count, not with the square footage on the listing.
• System pressure and static pressure issues. Sometimes ducts are leaking because the air handler is oversized or undersized for the ductwork. Sealing a system that’s already starved for return air doesn’t fix the problem. If we see this during inspection, we tell you before you spend money on the wrong repair.

Why Los Angeles Duct Work Costs What It Costs

Ductwork pricing in LA looks higher than in most of the country for a simple reason: the housing stock here is older, denser, and more seismically active than almost anywhere else. A home built in 1952 in the Crenshaw district has ductwork that’s 74 years old. The metal may still be sound, but every joint has moved at least a hundred times. Sealing that system is not a cosmetic job; it’s restoration work on a piece of infrastructure that’s outlived its original installers.

Then there’s the access problem. Los Angeles homes are packed tightly, which means many properties have no attic ladder, no crawlspace hatch that opens the way it should, or a furnace closet so small the technician works sideways. Every one of those constraints adds hours. A job that takes three hours in a Dallas attic can take six in an Echo Park bungalow. We price that honestly rather than absorbing it and cutting corners on the seal.

We also work in the neighborhoods where duct cleaning and sealing genuinely matter more than they do in newer construction. If you’re in one of the following areas, ask us for the local considerations when you call:

• San Fernando Valley (Van Nuys, Sherman Oaks, Encino, Northridge) – hottest attics, worst heat cycling
• San Gabriel Valley (Pasadena, Alhambra, Arcadia, Monrovia) – older sheet metal, seismic joint separation
• Westside (Santa Monica, Culver City, West LA) – ocean air, salt exposure, moderate temps but older homes
• Downtown and surrounding (Silver Lake, Echo Park, Highland Park, Koreatown) – historic bungalows, tight access
• South Bay (Torrance, Gardena, Redondo Beach) – 1950s tract homes with original flex and metal
• Hillside neighborhoods (Hollywood Hills, Mount Washington, Pacific Palisades) – pest pressure and irregular system design

The point is this: LA is not one market for ductwork. It’s fifteen. We quote each one based on what we actually find, not a flat rate pulled from a manual.

Repair vs. Replace: Which Makes Sense in Los Angeles?

Most homes we inspect can be repaired and sealed rather than fully replaced. Full duct replacement on an average LA single-family home runs $3,500 to $8,000 and is rarely necessary if the existing runs are sound. Sealing and repairing the same system often delivers the same performance improvement for a third of the cost.

That said, there are signs replacement is the better call:

• Duct runs are more than 20 years old and failing at multiple points
• The outer jacket is desiccated to the point the duct crumbles in your hand
• Rigid sheet-metal runs have rusted through or been so damaged that patching creates a longer-term liability
• The layout itself is the problem, not the duct – undersized trunks, sharp 90-degree elbows, runs that dead-end into nothing
• Rodent damage has spread through more than 30% of the system

When replacement is the honest answer, we say so in writing before you commit. When sealing is enough, we say that too. No upsell.

The 365-Day Done Right Promise

Every duct repair and sealing job we do is covered by the 365-Day Done Right Promise. That’s a written guarantee, not a handshake: if a seal we installed fails within twelve months, or a repair we made comes apart, we return and make it right at no charge. Free second visit included. If we have to come out three times, we come out three times. You’re not paying for us to learn the first time.

Most companies in this trade don’t offer a full year in writing. It’s the reason we price work honestly the first time and inspect before we quote. A cheap seal that fails in six months is not cheaper than the one that holds.

How to Save on Duct Repair & Sealing

Straight talk: you don’t have to spend the top of the range to get a properly sealed system. Here’s how LA homeowners keep their costs down without cutting into the quality of the work.

• Get it inspected before the repair, not after. A free estimate with a pressure test tells you where the leaks actually are. Paying to seal a joint that wasn’t leaking is money for nothing.
• Bundle cleaning and sealing. As noted above, one visit for both jobs costs less than two separate visits, because the equipment setup and the site access are already paid for.
• Do the easy access prep yourself. Move the holiday boxes, clear the attic hatch, and make sure the crawlspace opening is actually openable before the crew arrives. Then you’re paying for duct work, not for moving lawn chairs out of the way.
• Handle minor register leaks yourself only if they’re accessible and safe. Sealing an exterior grille with paintable mastic doesn’t require equipment. But anything involving cutting into the duct, resetting a trunk, or working in a tight attic is best left to a trained technician – the risk of damaging the foil jacket or falling through a ceiling is real.
• Address small leaks before they become big ones. An $85 seal on a boot connection today prevents a $400 loose-trunk repair in two years. If you notice a register blowing weak or a room that won’t cool right, call before the system tells you the hard way.
• Ask about filter cabinet sealing at the same time. A leaky filter door on a high-MERV system pulls in attic dust. Sealing the cabinet while we’re already set up is a small add-on.
• Take the free estimate every time. We price free and write it down before we touch anything. Call (361) 326-5060 and we’ll schedule it around you.

One more thing worth saying: the cheapest bid in LA is usually the one that ends up costing you twice. We’ve walked into homes where a homeowner paid $350 for a “seal job” that was a smear of mastic across three joints and a promise. Six months later, the same leaks. The 365-Day Done Right Promise exists because we’re tired of that story. If you’re tired of it too, that’s who we’re here for.

FAQs – Duct Repair & Sealing Cost

How much does duct sealing cost in Los Angeles in 2026?

Duct sealing in Los Angeles runs $450 to $1,600 depending on how many runs need sealing and how accessible they are. A condo with 8 accessible runs typically lands under $700. A 2,500 square foot San Fernando Valley home with 22 runs and a partially obstructed attic typically lands between $1,100 and $1,500. Call (361) 326-5060 for an exact quote – estimates are free and written.

Is duct sealing worth the money in Los Angeles?

Yes, particularly in older LA homes. Typical duct systems lose 20% to 30% of conditioned air through leaks, which means you’re paying to cool the attic. Sealing a leaking system usually pays back in energy savings within two to four summers, then continues saving. In LA’s older housing stock, the combination of aging joints and seismic movement makes duct sealing one of the highest-return home improvements you can make. Call (361) 326-5060 to schedule a free estimate and we’ll tell you what your system is actually losing.

How much does it cost to repair a crushed or disconnected duct in Los Angeles?

Replacing a crushed or disconnected duct run in LA typically costs $175 to $375 per run for flex duct, or $400 to $900 per section for rigid sheet metal. Disconnected trunk lines usually run $300 to $700 because they involve re-securing the main line and sealing it. If more than a few runs are damaged, we quote the whole repair as one written price so you’re not adding up surprises. Call (361) 326-5060 for a same-week inspection.

Can you repair ductwork the same day?

Yes, for most common repairs. If your ducts are accessible and the damage is limited to sealing joints, reconnecting a boot, or replacing a couple of flex runs, we can usually complete the work in a single visit the same day we inspect. Larger jobs – full-system sealing, multiple rigid section replacements, or work in a crawlspace that requires prep – are typically scheduled within a few days. In an emergency (a completely disconnected trunk in summer), call (361) 326-5060 and we’ll do what we can to get out same day.

How long does duct sealing last?

A properly sealed duct system using mastic and mechanical fastening typically holds for 10 to 15 years in a Los Angeles attic, and often longer in a conditioned space. Heat cycling in San Fernando Valley and San Gabriel Valley attics is the main factor that shortens that window. We use professional-grade mastic and, where needed, mesh tape reinforcement at every joint, so the seal doesn’t dry and crack the way cheap foil tape does. Every seal we install is backed by the 365-Day Done Right Promise. Call (361) 326-5060 with any questions about how the guarantee works.

Why Hollis Air Duct Cleaning for Duct Sealing in Los Angeles

Hollis Air Duct Cleaning has been in business since 2004, part of the Garrison Partners family. Every location is independently owned and operated under The Garrison Standard, which means the prices are written, the technicians are background-checked and uniformed, and the site is left cleaner than we found it. Our crews work with professional equipment from Rotobrush, Nikro, Abatement Technologies, Honeywell, Aprilaire, and Guardsman – the same tools commercial air quality crews use. Roy Castellanos and the team here in Los Angeles run every job by The Garrison Code: show up inside the window, price in writing, complete the job by the book, and leave the site clean.

We don’t run teaser pricing. We don’t surprise you at the door. We don’t leave a mess for you to clean up. What we do is inspect the system, write down the price, do the work, test the result, and stand behind it for a full year. If you want a written price and a real guarantee on duct repair and sealing in Los Angeles, call (361) 326-5060 for a free estimate. We answer the phone live, 24 hours a day, 7 days a week. You won’t get a voicemail loop here.

Pricing reflects the Los Angeles market as of 2026. Hollis Air Duct Cleaning offers free estimates – call (361) 326-5060.

Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Los Angeles since 2004.