LC Heating & Air provides professional duct sealing services to help Larchmont homeowners stop energy waste and improve indoor comfort. We use diagnostic testing to find leaks and apply the right sealing method for your home's specific ductwork.
Larchmont Village and the surrounding neighborhoods are known for their historic character, but those beautiful older homes often come with HVAC challenges. Many homes in this area were built long before central air was standard, meaning ductwork was often added later in tight spaces or attics. If your system is struggling to keep rooms at the same temperature or your energy bills seem high, the problem is often leaky ducts, not just the equipment itself.
At LC Heating & Air, I focus on the practical side of HVAC. I don't believe in selling you a new system if your current one just needs a proper seal to work efficiently. My team and I serve Larchmont homeowners by identifying exactly where your conditioned air is escaping into attics or wall cavities and fixing it with durable, long-term solutions. We are based right nearby on Fairfax Avenue and bring a straightforward, honest approach to every job.
Local HVAC considerations
Larchmont, including Larchmont Village, Plymouth Boulevard, and Rossmore Avenue
CSLB #1073586
(323) 970-3113
Why Duct Sealing Matters in Larchmont
In Larchmont, we see a lot of homes with original sheet metal or aging flex ductwork. Over time, the joints and connections in these systems loosen, or the material itself degrades. When your ducts leak, you are essentially paying to air-condition your attic or crawl space instead of your living room. This is a common pattern in our local housing stock, especially in homes where HVAC systems were retrofitted into existing architecture.
Duct sealing is one of the highest-ROI home energy improvements available. Studies of California homes consistently show 20–30% duct leakage in older homes. By sealing these leaks, we ensure that the air your system works hard to cool or heat actually reaches the rooms where you spend your time. It’s a permanent fix that makes a noticeable difference in both comfort and monthly utility costs.
Working With Larchmont's Historic Architecture
Larchmont is defined by its Craftsman bungalows, Spanish Colonial Revival, and Tudor homes. These structures are beautiful, but they present specific constraints for HVAC technicians. We often find undersized ductwork or limited access in attics and crawl spaces. Before we recommend any repair or sealing, we check the electrical capacity, duct condition, and equipment placement to ensure our work won't disrupt the character of your home.
We also keep a close eye on older construction details. In some pre-1960 homes, we may encounter asbestos-wrapped ducts. We always assess these factors upfront so there are no surprises. Our goal is to provide a solution that fits your home's specific needs, not a generic, one-size-fits-all approach.
Our Diagnostic Process
I don't guess when it comes to your HVAC system. We start every project with a duct blaster test to quantify exactly how much air you are losing. This test gives us a baseline percentage of system airflow leakage. It’s the only way to know for sure if your ducts are the primary culprit for your comfort issues.
Once we have the data, we select the right approach. For accessible joints and plenums, we use manual mastic sealing. For distributed leaks in inaccessible areas, we use the Aeroseal process. After the work is finished, we run the duct blaster test again to verify the improvement and provide you with the documentation.
Repair vs. Replacement: An Honest Look
A common question I get is whether it's better to seal old ducts or just replace them. If your ductwork is structurally sound but just leaky at the joints, sealing is usually the smarter, more cost-effective choice. However, if the ducts are crushed, undersized, or made of deteriorating material, sealing won't solve the airflow problem.
If the system is worth repairing, I will tell you. If the pattern points to replacement, I will explain why. We want you to have a system that fits your home, not just a quick fix that fails in a year. We provide written estimates so you can make an informed decision before we start any work.
Understanding Costs
We believe in transparency. Our duct sealing costs vary based on the size of your home and the complexity of the ductwork. 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 work.
When considering the cost, remember that sealing can reduce HVAC energy use by 15–25%. At current LA electricity rates, the payback period is often under two years. We focus on providing a permanent solution that lasts for the life of the duct system.
Common Mistakes to Avoid
The biggest mistake I see is the use of standard silver 'duct tape' on HVAC systems. It dries out, loses its adhesive, and falls off within a few years. We only use professional-grade mastic or foil-backed HVAC tape that is designed to stay pliable and hold a seal for the long haul.
Another mistake is ignoring the ductwork when replacing an HVAC unit. If you install a high-efficiency furnace or AC unit but leave the leaky, undersized ducts in place, you aren't getting the efficiency you paid for. We always recommend checking the duct system integrity whenever you are planning an HVAC equipment replacement.
Health and Safety Considerations
Your safety is our priority. When we perform Aeroseal, we use a non-toxic vinyl acetate polymer—the same material found in chewing gum. While it is safe, we recommend that homeowners vacate the property for about 60–90 minutes during the injection process as a precaution. You can return as soon as the process is complete and the system has run briefly to clear the air.
We also ensure that all our work complies with California Title 24 standards. This includes proper testing and documentation for permit compliance, which is essential if you are doing this work as part of a larger HVAC replacement project.
Is Duct Sealing Right for You?
Duct sealing is a great investment if you have high energy bills, uneven temperatures, or an older home that has never had its ducts inspected. It’s a permanent upgrade that improves the performance of your existing HVAC system.
If your ducts are in good condition but leaking at the joints, sealing is almost always the right choice. If your ducts are falling apart or undersized, we will tell you that replacement is the better path. We provide the facts so you can make the decision that makes the most sense for your home and your budget.
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
Our duct sealing process in Larchmont
Reviewed by Leo, Owner & Lead Technician
This duct sealing guide for Larchmont 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 Larchmont customers say about duct sealing
Verified reviews from homeowners in Larchmont 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.”
