HVAC duct sealing in LA — where 30% of your energy goes.
Most LA homes built before 2000 lose 20-35% of HVAC energy through duct leaks. Aeroseal, manual sealing, and full duct replacement compared. Real LA install costs and savings.
Duct sealing options for LA homes.
| Method | Cost (typical 2,000 sq ft home) | Result Level | Best For |
|---|---|---|---|
| Manual mastic + tape sealing | $800-$2,200 | 75-85% tightness | Accessible ducts in attic or crawlspace |
| Aeroseal (automated injection) | $1,800-$3,800 | 95%+ tightness (certified) | Hard-to-access ducts in walls or concealed |
| Full duct replacement | $4,500-$11,500 | 100% (new R-8 insulated) | 30+ year old ducts, asbestos, fiber degradation |
Why LA ducts are usually worse than average.
Three factors combine to make LA ducts leakier than national average:
- →Older housing stock — much of LA was built 1925-1970 with original ductwork. Tape-sealed seams degrade over 30+ years.
- →Attic-installed ducts — LA’s mild climate let builders install ducts in unconditioned attics. Heat cycling degrades sealing materials faster.
- →Earthquake stress — 1994 Northridge + decades of smaller events have separated joints and torn flex duct.
HUS install data shows 73% of pre-2000 LA homes have 25%+ duct leakage. That’s $400-$700/yr in wasted HVAC energy for a typical home.
Aeroseal — the gold standard.
Aeroseal is a patented automated duct sealing process developed at Lawrence Berkeley National Laboratory. The process:
- Technician seals registers and the return air opening.
- Pressurizes the duct system to a controlled level.
- Injects an aerosol sealant (water-based vinyl acetate polymer) into the duct stream.
- The sealant particles flow with the pressurized air and bond to the EDGES of leaks (not the open passageway), sealing holes up to 5/8 inch.
- Software measures leakage before and after, providing a certified seal level.
Takes 4-8 hours. Costs more than manual sealing but the certified seal level + access to hidden ducts (inside walls, concealed runs) makes it the right choice for most LA homes.
When to replace ducts entirely.
- →Asbestos-wrapped ducts — pre-1980 LA homes sometimes have asbestos-containing duct insulation. Must be removed by certified abatement contractor before replacement. Sealing is NOT a substitute.
- →Internal fiber degradation — old flex duct internal lining breaks down and contaminates indoor air. Requires replacement.
- →Severely undersized or wrong-routed ducts — original installs that never delivered proper airflow. Replacement enables system right-sizing.
- →Major HVAC upgrade — when replacing 20+ year HVAC system, replacing ducts simultaneously often makes sense (incremental cost is lower with both crews already on site).
Real LA savings examples.
| Home | Pre-Sealing HVAC Cost | Post-Aeroseal Cost | Savings |
|---|---|---|---|
| Burbank 2-bd, 1950s ranch (35% leakage) | $1,720/yr | $1,255/yr | $465 (27%) |
| Sherman Oaks 3-bd, 1965 ranch (28% leakage) | $2,140/yr | $1,620/yr | $520 (24%) |
| Pasadena 4-bd, 1948 Spanish (32% leakage) | $2,580/yr | $1,915/yr | $665 (26%) |
Payback: typically 4-7 years on Aeroseal investment.
Free duct leakage test.
We measure your actual leakage rate, then recommend the right approach (manual sealing, Aeroseal, or replacement). Most LA homes recover the investment in 4-7 years.
