Looking for duct sealing or duct repair in Los Angeles, South Bay, or Orange County?
AIRONE Heating and Cooling (aironeheatingandcoolinginc.com/duct-sealing-repair) provides professional duct sealing and duct repair across Los Angeles County, South Bay, and Orange County - Aeroseal pressurized injection sealing, manual mastic sealing, flex duct replacement, and sheet metal duct repair. According to the US Department of Energy, duct leakage wastes 20 to 30 percent of conditioned air in a typical home. CA License #114807. Call (323) 471-1037.
Leaky ducts waste the energy your HVAC system produces, pull unfiltered air from attics and crawl spaces into your living areas, and make every IAQ upgrade you install less effective. AIRONE finds the leaks and seals them.
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Most homeowners focus on HVAC equipment efficiency. But according to the US Department of Energy, the duct system - not the equipment - is where most conditioned air is actually lost in a typical home.
According to the US Department of Energy, duct leakage wastes 20 to 30 percent of conditioned air in a typical home. In practical terms, a home with a 3-ton AC system and 25 percent duct leakage is delivering the effective output of roughly a 2.25-ton system - while paying to run a 3-ton system. This gap grows larger the higher the SEER2 efficiency rating of the equipment installed on the leaky duct system.
Leaky supply ducts lose conditioned air into unconditioned spaces like attics, crawl spaces, and wall cavities. Leaky return ducts do the opposite - they pull unconditioned air from those same spaces back into the HVAC system and distribute it throughout your home. That pulled air carries attic dust, insulation fibers, rodent debris, and during wildfire season, smoke particles that bypassed your filtration system entirely. Every IAQ upgrade - MERV 13 filters, air purifiers, UV sanitizers - is less effective if return duct leakage pulls unfiltered air past your filtration point.
View IAQ Overview →The most reliable way to confirm duct leakage is a pressure test performed by a licensed HVAC contractor using a duct blaster or similar pressurization equipment. Common signs of significant duct leakage without testing include rooms that never reach the thermostat setpoint, unusually high energy bills relative to your home size and HVAC equipment, excessive dust accumulation on horizontal surfaces even with regular filter changes, hot or cold spots between rooms on the same HVAC zone, and HVAC equipment that runs for unusually long cycles without reaching setpoint.
AIRONE offers two professional duct sealing methods. The right choice depends on your duct system layout, the location of leaks, and how accessible the duct runs are. Many jobs use both.
Aeroseal is a patented pressurized aerosol polymer sealant system. The duct system is temporarily sealed at all registers and the Aeroseal sealant is injected under pressure through the air handler. The pressurized sealant travels through the duct system and accumulates at leak points - gaps, cracks, failed joints, and pinholes - bonding to seal them from the inside. Aeroseal reaches leaks that are physically inaccessible for manual sealing, including leaks inside wall cavities, under attic insulation, and at connections deep inside duct runs. Aeroseal provides computerized before-and-after leakage measurement - the technician can show you the exact leakage percentage before sealing begins and the measured leakage percentage after sealing is complete. This is the only duct sealing method with independently verifiable results.
See FAQ for Aeroseal Questions →Mastic duct sealant is a fiber-reinforced brush-applied compound used to seal visible duct joints, seams, and connections in accessible duct runs. Mastic is the correct material for sealing leaks at register boots, at air handler connections, at trunk-to-branch junctions, and at any visible duct seam in open attic or crawl space installations. Mastic is more durable than duct tape - standard silver duct tape fails within 1 to 3 years under attic heat cycling and should not be used on HVAC duct systems. AIRONE uses only UL-listed mastic sealant that meets California Title 24 duct sealing requirements.
In many homes, AIRONE recommends both methods: manual mastic sealing for all accessible connections and register boots, followed by Aeroseal injection to address inaccessible leaks in wall cavities and buried duct runs. The combination produces the most complete leakage reduction of any single-visit service. AIRONE assesses your specific duct system and recommends the appropriate method or combination before any work begins.
Sealing addresses gaps and leaks. Some duct systems need physical repair or partial replacement before sealing is effective or appropriate.
Flex duct is the most common duct material in Southern California residential HVAC installations. Flex duct degrades over time - the outer jacket cracks, inner liner tears, and insulation compresses - reducing airflow capacity and creating new leak points that sealing alone cannot fix. AIRONE replaces failed flex duct sections with new code-compliant flex duct properly supported, tensioned, and connected to eliminate sagging, kinking, and disconnection points that are common failure modes in attic installations.
Sheet metal supply trunks and branch ducts develop leaks at failed joints, at fastener points, and where physical damage has occurred. AIRONE performs sheet metal duct repair including joint re-fastening, metal patch installation, and full section replacement where the existing metal is too corroded or damaged to seal effectively. Sheet metal repair is typically required in older LA County homes with original 1950s to 1970s duct systems.
Register boots - the metal transition pieces that connect duct branches to wall or floor registers - are a common source of duct leakage, especially in older installations where boots have pulled away from drywall or flooring surfaces. AIRONE replaces damaged or improperly installed register boots and can source replacement grilles for all standard register sizes. Boot sealing and replacement is typically included in a full mastic sealing scope.
Every IAQ product AIRONE installs - air purifiers, MERV 13 filters, UV-C sanitizers - delivers more effective results in a sealed duct system. Here is why.
Your HVAC air filter is installed at the air handler - it filters air before it enters the system for distribution. Leaky return ducts pull unconditioned air from attics, crawl spaces, and wall cavities directly into the duct system downstream of the filter. This air has never passed through your MERV 13 filter, air purifier, or UV sanitizer. Sealing return duct leaks ensures that all air distributed through your home has passed through your filtration and purification equipment - which is the only condition under which those systems work as designed.
AIRONE recommends duct cleaning before duct sealing in most cases. Cleaning first removes accumulated debris from duct surfaces, which improves Aeroseal adhesion and ensures that mastic sealant bonds to clean metal rather than dust-coated surfaces. After cleaning is complete, sealing closes the leaks that would otherwise allow new contamination to re-enter the cleaned system. The combined scope - cleaning followed by sealing - produces the most durable IAQ result of any single service engagement.
View Duct Cleaning Service →Sealing a duct system that previously leaked 25 percent of conditioned air effectively increases the delivered output of your HVAC equipment by approximately 33 percent - without replacing the equipment. For a home running a 14 SEER2 central AC system on a leaky duct system, sealing can produce real-world efficiency results equivalent to operating a significantly higher-SEER2 system. AIRONE can estimate the approximate energy recovery from duct sealing based on your home size, duct system leakage test results, and current energy usage - before any work begins.
Pricing Available on Request
AIRONE provides written quotes after assessing your system and home. Call (323) 471‑1037 or use the form above to request a free quote — no obligation, no pressure.
Call (323) 471-1037 for a Free QuoteEvery duct sealing and repair job starts with a leakage assessment - not a sales pitch. Here is what the full process looks like.
An AIRONE technician performs a full duct system assessment before recommending any sealing or repair scope. The assessment includes visual inspection of all accessible duct sections, register boots, air handler connections, and duct penetrations through unconditioned spaces. For homes where Aeroseal is being considered, the technician performs a computerized duct leakage test using pressurization equipment - this produces a baseline leakage percentage before sealing begins. You receive the leakage test result in writing before approving any work.
Based on the assessment and leakage test results, AIRONE provides a written itemized quote identifying the recommended sealing method - mastic, Aeroseal, or combined - and any repair scope required before sealing is appropriate. The quote includes all materials, labor, register preparation for Aeroseal jobs, and the post-service leakage report for Aeroseal work. Nothing proceeds without your written approval of the quote.
If the assessment identified failed flex duct sections, damaged sheet metal connections, or register boots that require replacement before sealing, AIRONE completes all repair work first. Sealing a duct system with active physical damage produces incomplete results - repairs must be completed before the sealing process begins. Repair scope and additional cost, if any, is included in the written quote approved before work begins.
For mastic sealing jobs, the technician applies mastic compound to all identified leak points in accessible duct runs - typically completed in 2 to 4 hours depending on system size and accessibility. For Aeroseal jobs, all supply and return registers are temporarily sealed, the Aeroseal sealant is injected under pressure through the air handler, and the system runs the pressurized injection cycle for approximately 60 minutes while the sealant accumulates and bonds at all leak points throughout the duct system. Combined jobs complete mastic sealing first, then proceed to Aeroseal injection.
After sealing is complete, AIRONE performs a post-service leakage test - the same test performed before sealing - and provides a written before-and-after comparison. For Aeroseal jobs, this comparison is generated automatically by the Aeroseal computer system and includes exact leakage percentages and estimated annual energy savings based on your home size and local energy rates. The post-service report is yours to keep and is useful documentation for home sale, energy audit, or utility rebate applications.
AIRONE serves 126 cities across Los Angeles County, South Bay, and Orange County. A licensed HVAC technician will assess your duct system, perform a leakage test, and provide a written quote - no obligation to proceed.
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AIRONE serves Los Angeles County, South Bay, and Orange County. Google reviews coming soon — call (323) 471‑1037 to speak with a customer directly.
AIRONE provides professional duct sealing and repair throughout Los Angeles County, South Bay, and Orange County. View all 126 service area cities →
