Professional duct sealing services from LC Heating & Air. We identify and seal leaks in your ductwork to improve efficiency, comfort, and indoor air quality in your Sylmar home.
Duct Cleaning & Air Duct Service in Sylmar
LC Heating & Air provides duct cleaning in Sylmar — including air duct cleaning, duct repair service, duct sealing, HVAC ductwork. Whether you need same-day service, a written estimate, or help deciding between repair and replacement, our licensed technicians handle every make and model.
We repair and service all major HVAC brands in Sylmar, including Carrier, Trane, and Goodman, and older or discontinued units. No matter the manufacturer, we diagnose the problem accurately and give you an upfront price before any work begins.
If your HVAC system is running constantly but your home still feels unevenly heated or cooled, the problem might not be the equipment itself. Often, the issue is the ductwork. In Sylmar, where we deal with significant attic heat gain and mixed-age housing, conditioned air frequently leaks into attics or wall cavities before it ever reaches your living room. At LC Heating & Air, we specialize in identifying these leaks and sealing them to ensure your system works as efficiently as it was designed to.
I'm Leo, and I believe in being honest about what your home actually needs. Duct sealing is one of the most effective ways to lower your energy bills and stop wasting money on conditioned air that never reaches you. Whether you have accessible sheet metal ducts or hidden flex ducting, we use professional diagnostic tools to find the leaks and provide a permanent, long-term solution.
Call LC Heating & Air at (323) 970-3113 for scheduling and estimates.
Local HVAC considerations
Common Duct Issues in Sylmar Homes
Sylmar's housing stock ranges from older homes with original ductwork to newer remodels. In many of these properties, we see common patterns: flex ducts that have been crushed during attic work, joints that have separated over time due to thermal expansion, and plenums that were never properly sealed during initial installation. When these ducts leak, your system loses pressure, forcing the blower motor to work harder and run longer just to maintain the temperature on your thermostat.
Another issue we see locally is dust accumulation. If you notice a fine layer of dust on your supply registers or near duct seams, it is a strong indicator that your return ducts are pulling in air from your attic or crawl space. This doesn't just hurt your energy efficiency—it also pulls dust, insulation particles, and allergens directly into your living space.
Why Duct Sealing Matters for Your Home
Whether you live in a single-family home or a small multifamily building, your duct system is the circulatory system of your HVAC. In our local climate, duct leakage is a major contributor to high utility bills. When 20–30% of your air leaks out before it reaches the vent, your furnace or AC has to run 20–30% longer to compensate. By sealing these leaks, we can often reduce your energy usage by 15–25%.
We approach every home with a focus on the specific layout. We check for proper return sizing, insulation levels, and register balance. If your ducts are leaking, no amount of high-efficiency equipment will make your home comfortable. We make sure the foundation of your system—the ducts—is solid before we look at anything else.
Our Diagnostic Process
We don't guess. Before we recommend any work, we perform a duct blaster test. This is a standard procedure where we pressurize your duct system to measure exactly how much air is escaping. This gives us a baseline number so you can see the difference after we finish the job.
Once we have the data, we determine the best sealing method. If the leaks are at accessible joints or plenums, we use high-quality mastic. For leaks that are hidden inside walls or inaccessible attic spaces, we use the Aeroseal process. This technology injects a polymer mist that finds and seals leaks from the inside out, providing a permanent, non-toxic solution that is rated for the life of your duct system.
Repair or Replace?
A common question I get is whether to repair old ducts or replace them entirely. If your duct system is structurally sound but just has leaky joints, sealing is almost always the right move. However, if the ducts are crushed, collapsed, or made of outdated materials that are falling apart, sealing won't fix the airflow restriction. During our inspection, we look at the condition of the materials, the sizing, and the accessibility. If a repair is enough to get you back to comfort, I will tell you. If the system is beyond help, I will explain why replacement is the more practical long-term investment.
Understanding Costs and Value
Duct sealing is an investment that pays for itself. While manual mastic sealing typically ranges from $400 to $1,200, Aeroseal internal sealing for a standard home usually falls between $1,500 and $3,000. These costs include the diagnostic testing and the verification test to prove the work was done correctly. Because you are reducing the load on your HVAC system, you will see the return on this investment in your monthly utility bills. We provide a written estimate for every job so you know exactly what you are paying for before we start.
Access and Scheduling
In Sylmar, we work with a variety of home layouts, from single-story ranch homes to complex remodels. Access is a major factor in our work. We need to reach your plenums and main duct runs to perform a thorough job. When we schedule your service, we account for the time needed to safely access these areas. Most of our duct sealing projects are completed in a single day, meaning you won't have to deal with a long-term disruption to your home life.
Mistakes to Avoid
The biggest mistake I see is the use of standard silver 'duct tape.' It dries out, cracks, and falls off within a few years, leaving you with the same leaks you started with. We use professional-grade mastic and foil-backed HVAC tape that is designed to stay flexible and last for years. Another mistake is skipping the testing phase. Without a duct blaster test, you have no way of knowing if the sealing actually worked or if you just paid for someone to put tape on a few visible spots.
Health and Safety
Your indoor air quality is a priority. Leaky ducts don't just lose air; they pull air from dirty attics and crawl spaces into your home. By sealing your ducts, you prevent this 'dirty air' from circulating. We also ensure that all materials used, including the Aeroseal polymer, are safe and non-toxic. We are a licensed C-20 HVAC contractor (CSLB #1073586), and we follow all safety protocols to ensure the job is done right the first time.
Is Duct Sealing Right for You?
If you are planning to replace your HVAC equipment, you should absolutely consider duct sealing. California Title 24 requires duct leakage testing for new installations, and sealing your ducts beforehand ensures your new, expensive equipment isn't wasting energy pushing air into your attic. Even if you aren't replacing your system, sealing is a practical way to improve comfort in rooms that are always too hot or too cold.
At LC Heating & Air, we don't push services you don't need. If we find your ducts are in good shape, we will tell you. If we find they are leaking, we will show you the numbers and explain the fix. Give us a call at (323) 970-3113 to discuss your system.
How the visit works
We perform a duct blaster test to quantify existing leakage as a percentage of system airflow.
Based on leakage quantity, duct type, and accessibility, we recommend manual sealing, Aeroseal, or a combination.
We apply mastic to all accessible joints and plenums, or set up and run the Aeroseal process for internal sealing.
We re-run the duct blaster test and provide you with before/after leakage numbers as written documentation.
Cost factors we review before quoting
- • Duct inspection: $125–$200
- • Duct cleaning (whole house): $400–$900
- • Duct sealing: $1,000–$3,000
- • Duct repair or replacement: $500–$5,000
Useful next steps
Duct Sealing in Sylmar at a glance
- • Duct Sealing provider: LC Heating & Air
- • Location served: Sylmar, CA 91342
- • License: CSLB C-20 #1073586
- • Phone: (323) 970-3113
- • Estimate: written estimate before approved work
- • Emergency calls answered within 30 minutes (24/7)
Our duct sealing process in Sylmar
Reviewed by Leo, Owner & Lead Technician
This duct sealing guide for Sylmar is reviewed for practical HVAC accuracy by Leo at LC Heating & Air. LC Heating & Air holds California CSLB C-20 HVAC license #1073586 and provides written estimates before approved work.
What Sylmar customers say about duct sealing
Verified reviews from homeowners in Sylmar and nearby neighborhoods who used our duct sealing service.
“Our AC stopped working during a heat wave and LC had a technician here within two hours. He diagnosed a bad capacitor, had the part on his truck, and fixed it on the spot. Fair price, no upsell. Will use again.”
“Called on a Saturday because AC was blowing warm air. LC answered, sent someone the same afternoon. They found and fixed a refrigerant leak. Professional and reasonably priced.”
“Woke up to no AC at 6am. LC was at my door by 9am. Frozen evaporator coil — they explained exactly why it happened (dirty filter + low airflow) and fixed it same visit. Very professional.”
