54ยฐF in Altadena ยท Cool โ€” great time for a furnace check.

Duct Sealing in Altadena, CA

Professional duct sealing โ€” stop energy loss and improve whole-home comfort. Serving Altadena and surrounding neighborhoods.

(323) 970-3113Free estimate
CSLB #1073586
5.0โ˜… Google
20+ Years in LA
Same-day service
Free written estimate
24/7 emergency

When Altadena residents need duct sealing, LC Heating & Air delivers same-day service backed by 20+ years of working in the LA market. Altadena is an unincorporated community nestled against the San Gabriel Mountains directly north of Pasadena. The neighborhood experienced devastating impacts from the 2025 Eaton Fire, which destroyed homes and left airborne particulates throughout the community that require professional HVAC assessment and remediation. That local knowledge means our technicians arrive knowing what equipment and access challenges to expect โ€” cutting diagnostic time and getting repairs done faster.

### What Duct Sealing Accomplishes Duct sealing is one of the highest-ROI home energy improvements available to Los Angeles homeowners. When conditioned air leaks into attic or wall cavities before reaching the living space, you're paying to condition space you don't occupy. Studies of California homes consistently show 20โ€“30% duct leakage in older homes โ€” and every percentage point of leakage reduction shows up directly in your utility bill.

Overview

### Manual Sealing vs. Aeroseal LC Heating & Air offers two duct sealing approaches. Manual sealing uses mastic (a durable, flexible sealant applied by hand) and foil tape at accessible duct joints, take-offs, supply and return plenums, and connection points. This is the right approach when significant leakage locations are accessible and the duct system is in otherwise good structural condition. Aeroseal internal sealing is our solution for duct systems where significant leakage is distributed throughout the system in locations that aren't manually accessible โ€” it seals from the inside out using a pressurized polymer aerosol that deposits on and seals leak sites as air passes through them.

### California Energy Code and Duct Sealing California Title 24 requires duct sealing testing (duct blaster test) as part of any HVAC replacement permit โ€” and requires that systems failing the test be sealed to meet the leakage standard before permit signoff. If you've replaced HVAC equipment without a permit, or had a permitted replacement that failed to test the ducts, your system may have significant unsealed leakage.

### What You'll Notice After Duct Sealing Homeowners consistently report three immediate improvements after duct sealing: rooms that were previously hard to condition are now comfortable, the HVAC system runs for noticeably shorter cycles to reach the thermostat setpoint, and utility bills decrease. These improvements are permanent โ€” properly applied mastic and Aeroseal are rated for the life of the duct system.

Local HVAC Challenges

The 2025 Eaton Fire created an acute HVAC challenge for Altadena: smoke and ash infiltration into duct systems, contaminated air filters, and soot deposits on evaporator coils and heat exchangers. Homes in the fire's path need complete duct inspection and cleaning, filter replacement with HEPA-grade filtration during the remediation period, and in some cases coil replacement where heat damage has compromised efficiency. Beyond fire impacts, Altadena's foothill location means properties face wildfire risk generally and should invest in air quality measures including MERV 13+ filtration and whole-house air purification.

Neighborhood Context

Altadena's mountain proximity means cooler overnight temperatures in winter โ€” heating demand is higher than in the LA basin, and furnace maintenance is correspondingly more important. Many Altadena homes have gas furnaces that provide critical heating during December through February when overnight temperatures can drop into the 30s. We provide thorough furnace inspection including heat exchanger integrity testing, combustion analysis, and gas connection verification โ€” all essential safety checks that protect your family from carbon monoxide exposure.

Why Choose Us

Immediate energy savings: Sealing 20โ€“30% duct leakage typically reduces HVAC energy use by 15โ€“25%. At LA electricity rates, payback is often under 2 years.
Both methods available: Manual mastic sealing for accessible leaks, Aeroseal internal sealing for inaccessible distributed leakage โ€” we use the right approach for each system.
CA Title 24 compliance: We perform duct blaster testing before and after sealing and provide documentation for permit compliance.
Permanent solution: Properly applied mastic and Aeroseal are rated for the life of the duct system โ€” not a temporary fix that degrades over time.

Call (323) 970-3113 for same-day duct sealing in Altadena. We answer 24/7 โ€” emergencies and scheduled appointments alike. Licensed, insured, CSLB #1073586.

Why LC Heating & Air
20+ years serving LA
5.0โ˜… on Google (300+ reviews)
CSLB Licensed #1073586
Written estimate before work begins
Same-day service available
12-month labor warranty
24/7 emergency calls
All brands serviced
Call (323) 970-3113Request free estimate

Our duct sealing process in Altadena

STEP 01
Pre-sealing duct leakage test
We perform a duct blaster test to quantify existing leakage as a percentage of system airflow.
STEP 02
Sealing approach selection
Based on leakage quantity, duct type, and accessibility, we recommend manual sealing, Aeroseal, or a combination.
STEP 03
Duct sealing
We apply mastic to all accessible joints and plenums, or set up and run the Aeroseal process for internal sealing.
STEP 04
Post-sealing verification test
We re-run the duct blaster test and provide you with before/after leakage numbers as written documentation.
Verified Reviews

What Altadena customers say about duct sealing

Verified reviews from homeowners in Altadena and nearby neighborhoods who used our duct sealing service.

5.0 โ˜… Google
300+ verified reviews

โ€œLC replaced our entire HVAC system โ€” new Carrier condenser, furnace, and coil. Leo walked us through every option without pressure. The install team was professional and clean. System runs perfectly and our electricity bill dropped about 30%.โ€

D
David K.
Pasadena, CA ยท Nov 2025

โ€œWe were skeptical about a heat pump for heating in the winter but LC explained the technology clearly. After one winter season, our home stays warmer than it ever did with the old furnace, and it's quieter too.โ€

B
Brian Y.
Pasadena, CA ยท Feb 2026

โ€œAfter the Eaton Fire, our ducts smelled like smoke. LC did a full cleaning โ€” negative air pressure, rotary brushes, the works. Air quality in our home is completely different now. They were sensitive to what our neighborhood went through.โ€

M
Mark D.
Highland Park, CA ยท Mar 2025
Read all 300+ Google reviews โ†’
Frequently asked questions

Duct Sealing in Altadena โ€” common questions

How fast can LC Heating & Air respond to a duct sealing call in Altadena?
We offer same-day duct sealing service throughout Altadena. For emergencies, we aim to arrive within 60โ€“90 minutes. Call (323) 970-3113 any time โ€” we answer 24/7.
Is LC Heating & Air licensed to do duct sealing work in Altadena?
Yes. LC Heating & Air holds California Contractors State License Board license #1073586. We are fully licensed and insured for all HVAC work in Altadena and throughout LA County.
Do you provide a free written estimate for duct sealing in Altadena?
Yes. Every job starts with a free written estimate. You approve the price before we touch anything. No surprises, no mystery charges. If we find additional issues during the job, we discuss them with you before doing any additional work.
How much energy can duct sealing save in Altadena?
Studies of California homes find average savings of 15โ€“25% of HVAC energy use after professional duct sealing. The actual savings depend on your pre-sealing leakage rate โ€” a home with 30% leakage can save significantly more than a home with 10% leakage. We quantify your specific leakage before sealing so you can estimate your expected savings.
What is the difference between mastic and duct tape for sealing ducts in Altadena?
Standard "duct tape" (the silver cloth tape) is not suitable for HVAC ductwork โ€” it dries out and fails within a few years. Mastic is a thick, flexible sealant applied with a brush or by hand that remains pliable and adheres permanently. Foil-backed HVAC tape (not cloth duct tape) is also suitable for certain applications. We use mastic on joints, plenums, and connections where it will provide a long-term seal.
How does Aeroseal work in Altadena?
Aeroseal pressurizes your duct system and injects a fine mist of vinyl acetate polymer particles. As air escapes through leaks, the particles accumulate on the edges of the leak openings and progressively seal them โ€” the same mechanism that causes a cut to heal. Leaks up to 5/8" can be sealed. A computer monitors leakage reduction in real time and stops when the target is reached.
Is Aeroseal safe in Altadena?
Yes. The vinyl acetate polymer used in Aeroseal is the same material used in chewing gum and many food products. It's non-toxic and has been tested for indoor air quality impacts. The Aeroseal process includes a testing phase that confirms the interior of your ducts is clean before sealing, and the sealant remains in the duct walls, not in the airstream after curing.
How much does duct sealing cost in Los Angeles in Altadena?
Manual mastic sealing of accessible duct sections: $400โ€“$1,200 depending on system size and accessibility. Aeroseal internal sealing: $1,500โ€“$3,000 for a typical single-story home. Both include before/after duct blaster testing. We provide a written estimate after the pre-sealing diagnostic.

More HVAC services in Altadena

AC Repair in AltadenaAC Installation in AltadenaAC Replacement in AltadenaCentral AC Service in AltadenaFurnace Repair in AltadenaFurnace Installation in AltadenaFurnace Replacement in AltadenaGas Furnace Repair in AltadenaHVAC Installation in AltadenaHVAC Replacement in AltadenaHVAC Maintenance in AltadenaMini Split Installation in AltadenaMini Split Repair in AltadenaHeat Pump Services in AltadenaHeat Pump Installation in AltadenaHeat Pump Repair in AltadenaDuct Cleaning in AltadenaDuct Repair in AltadenaAir Quality & IAQ in AltadenaCommercial HVAC in AltadenaCommercial AC Repair in AltadenaEmergency HVAC in AltadenaEmergency AC Repair in AltadenaEmergency Heating Repair in AltadenaHeater Repair in Altadena

Duct Sealing near Altadena

Duct Sealing in HollywoodDuct Sealing in West HollywoodDuct Sealing in Beverly HillsDuct Sealing in Mid-WilshireDuct Sealing in KoreatownDuct Sealing in Culver CityDuct Sealing in Hancock ParkDuct Sealing in Larchmont
Don't wait for it to break.
Same-day service, honest pricing, 20 years in LA.

Rapid Response Request