LC Heating & Air provides professional duct sealing to stop energy loss, improve airflow, and increase home comfort. We use manual mastic sealing and Aeroseal technology to ensure your system performs as intended.
In Los Angeles, your ductwork is the hidden engine of your HVAC system. If your ducts are leaking, you are essentially paying to air-condition your attic, crawl space, or wall cavities instead of your living room. At LC Heating & Air, we see many homes where 20% to 30% of conditioned air never reaches the intended room, forcing the system to work harder and run longer than necessary.
I am Leo, owner of LC Heating & Air. I believe in being honest about what your home actually needs. If your system is worth repairing, I will tell you. If the patterns in your ductwork point to a larger issue, I will explain why. We focus on practical, long-term solutions that make sense for your budget and your home's specific layout.
Local HVAC considerations
Los Angeles, CA 90036
CSLB #1073586
(323) 970-3113
Why Duct Sealing Matters in Los Angeles
Los Angeles homes vary significantly in age and construction, from older homes with original sheet metal to newer remodels with flex duct. A common pattern we see is conditioned air escaping into unconditioned spaces like attics or garages. This is particularly problematic during our intense heat waves, where the temperature difference between your ducts and the attic space is extreme.
When your ducts leak, you aren't just losing money on utility bills. You are also pulling in dust and contaminants from those unconditioned spaces, which then get distributed throughout your home. Sealing these leaks is one of the most effective ways to improve indoor air quality and ensure your HVAC system reaches the thermostat setpoint without constant cycling.
Understanding Your Home's Ductwork
Whether you live in a single-family home, a duplex, or a small multifamily building, the age of your property dictates the state of your ducts. In many older LA homes, we find ductwork that has degraded over decades. In newer remodels, we often find poorly installed flex duct that has been crushed or kinked, restricting airflow to specific rooms.
Before we recommend any sealing, we look at the whole picture: electrical layouts, equipment placement, and current duct condition. We don't just patch holes; we evaluate why the leaks are happening in the first place. This helps us decide if manual sealing or Aeroseal is the right path for your specific property.
Our Diagnostic Process
We start every duct project with a duct blaster test. This allows us to quantify exactly how much air is leaking from your system. It takes the guesswork out of the repair.
Once we have the data, we choose the right tool for the job. For accessible joints and plenums, we use high-quality mastic. For distributed leaks hidden inside walls or inaccessible attic spaces, we use the Aeroseal process. After the work is finished, we perform a second duct blaster test to verify the improvement and provide you with the documentation.
Repair vs. Replacement Decisions
A common question I get is whether to repair old ducts or replace them entirely. If the ductwork is structurally sound but just has leaky joints, sealing is a permanent, cost-effective fix. However, if the ducts are crushed, moldy, or improperly sized for your equipment, sealing won't solve the underlying airflow problem.
I will always give you a straight answer. If the system is worth repairing, we will tell you. If the pattern points to replacement, we will explain why. We want you to have a system that fits your property, not a generic recommendation that doesn't solve your comfort issues.
Understanding the Costs
Duct sealing costs vary based on the size of your home and the accessibility of the ducts. Manual mastic sealing typically ranges from $400 to $1,200, while Aeroseal internal sealing for a typical single-story home ranges from $1,500 to $3,000. These prices include the diagnostic testing required to verify the results.
When considering the cost, think about the long-term energy savings. Sealing 20–30% duct leakage typically reduces HVAC energy use by 15–25%. At current LA electricity rates, the payback period is often under two years. It is a practical investment that pays for itself through lower monthly bills.
Health and Safety Considerations
Your indoor air quality depends on clean, sealed ducts. Leaky ducts act like a vacuum, pulling dust, insulation fibers, and allergens from your attic or crawl space into your living area. By sealing these leaks, you stop that intake.
Regarding the Aeroseal process, it is perfectly safe. The polymer used is non-toxic—it is the same material used in chewing gum. We recommend that homeowners vacate the house for about 60 to 90 minutes during the injection process as a precaution, but you can return as soon as the system has run briefly to clear the air.
Common Mistakes to Avoid
The biggest mistake I see is the use of standard silver 'duct tape' on HVAC systems. It dries out, cracks, and fails within a few years. We only use professional-grade mastic or foil-backed HVAC tape that is designed to last for the life of the duct system.
Another mistake is ignoring the duct system during an HVAC replacement. If you install a high-efficiency unit but connect it to leaky, restrictive ducts, you are wasting your money. Always ensure your ductwork is tested and sealed as part of any major HVAC upgrade.
Access and Scheduling
We respect your time and your home. Most residential duct sealing projects are completed in a single day. Before we start, we assess your home's access points to ensure we can reach the necessary ductwork without causing damage.
If you are in Los Angeles, you can reach us at (323) 970-3113. We provide written estimates so you know exactly what to expect before we touch your equipment. We are fully licensed (CSLB #1073586) and ready to help you get your system running efficiently.
Is Duct Sealing Right for You?
If your HVAC system runs constantly but your home still feels unevenly heated or cooled, duct sealing is often the missing piece of the puzzle. It is a high-ROI improvement that addresses the root cause of energy waste.
If you are planning an HVAC replacement, sealing your ducts is the best way to ensure your new equipment performs at its peak. Give us a call at (323) 970-3113 to discuss your home's specific needs. We will perform a thorough inspection and provide a written estimate so you can make an informed decision.
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
- • Total square footage of the duct system
- • Accessibility of ductwork in attics or crawl spaces
- • Current leakage percentage
- • Choice between manual mastic sealing and Aeroseal
Useful next steps
Our duct sealing process in Los Angeles
Reviewed by Leo, Owner & Lead Technician
This duct sealing guide for Los Angeles 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 Los Angeles customers say about duct sealing
Verified reviews from homeowners in Los Angeles and nearby neighborhoods who used our duct sealing service.
“Had LC install a Daikin mini split in our 1940s bungalow that never had AC. The work was clean, the unit is incredibly quiet, and our bedroom finally stays cool in summer. Highly recommend.”
“We converted our garage into an ADU and needed HVAC. LC installed a Mitsubishi single-zone mini split — permits, electrical, everything. The unit is so quiet you can barely hear it running. Our tenant loves it.”
“Got a 3-zone Daikin system for our craftsman home — bedrooms upstairs, living room downstairs. Each room has its own temperature control and the monthly electric bill is actually lower than our old window units combined.”
