Aeroseal duct sealing is a process that uses pressurized aerosol particles to automatically locate and seal air leaks in HVAC ductwork from the inside. The system injects a proprietary sealant into the duct system while it's under slight positive pressure, allowing the particles to travel through the entire network and bond at leak sites.
This method targets small gaps and cracks that conventional tape or mastic cannot reach, especially in hard-to-access areas like attics, crawl spaces, or behind walls. Unlike manual sealing, which requires physical access to each joint, Aeroseal treats the entire system as a single unit, reducing labor and increasing coverage accuracy.
According to the U.S. Department of Energy, duct leakage can reduce HVAC efficiency by up to 30%, leading to higher energy bills and inconsistent indoor temperatures. Aeroseal addresses this by restoring duct integrity without invasive repairs. The process typically takes 2-4 hours and is performed by certified technicians using calibrated equipment.
The process begins with a diagnostic test to measure baseline airflow and identify major leakage points. A sealed access point is installed at the main supply plenum, and a specialized generator introduces a fine mist of sealant particles into the duct system. These particles remain suspended in the airstream until they encounter a leak.
When the particles reach a gap, they accumulate and form a durable, flexible seal. The sealant aims to adhere only to the edges of the leak, avoiding blockage of the duct interior. As sealing progresses, the system detects reduced airflow, indicating that the leaks are closing. The technician monitors pressure changes in real time to ensure complete coverage.
Once the system reaches equilibrium-typically when pressure stabilizes-the generator stops, and the sealant is allowed to cure. Final testing confirms a reduction in leakage, often achieving 90% or more sealing efficiency. The entire process is non-invasive and leaves no residue or odor.
The sealant used in Aeroseal is a water-based polymer blend engineered to withstand temperature fluctuations and maintain flexibility over time. It forms a permanent bond at leak sites but remains inert in the duct interior. The material is non-toxic and meets EPA standards for indoor air quality.
There are two primary system configurations: residential and commercial. Residential units are designed for homes with standard duct sizes (6-12 inches), while commercial systems handle larger ductwork (up to 36 inches) and higher airflow volumes. Both require calibration based on duct volume, layout complexity, and initial leakage levels.
| Type | Typical Use | Duct Size Range | Sealing Efficiency |
|---|---|---|---|
| Residential | Homes, townhouses | 6-12 inches | 85-95% |
| Commercial | Offices, schools, retail | 12-36 inches | 90-98% |
Some systems include real-time feedback via mobile apps, allowing technicians to adjust pressure and flow dynamically. This feature reduces trial-and-error and improves consistency across installations.
Aeroseal is commonly used in homes with older HVAC systems, particularly those built before 2000. In one study by the Lawrence Berkeley National Laboratory, homes with unsealed ducts lost an average of 20% of conditioned air through leaks. After Aeroseal treatment, average leakage dropped to less than 5%.
It's also effective in climates with extreme temperatures. In Phoenix, Arizona, a homeowner reported a 22% drop in cooling costs after sealing ducts in the attic. The system improved airflow distribution, eliminating cold spots in upper floors and reducing compressor runtime.
Another application is in multi-unit buildings where accessing individual duct joints is impractical. A property manager in Seattle used Aeroseal to treat 120 apartments in a single week. Manual sealing would have required 400+ hours of labor; the automated method took 16 hours total.
Many assume Aeroseal fills the entire duct with sealant. This is incorrect. The sealant only bonds at leak locations. Duct interiors remain clear and functional. The sealant is not sticky or gummy-it dries to a flexible, rubber-like film.
Another misconception is that it replaces all physical repairs. Aeroseal does not fix structural damage, such as torn ducts or collapsed sections. It only seals small gaps and micro-leaks. For major damage, mechanical repair is still necessary.
Some believe it's a one-time fix. While the seal is durable, environmental factors like thermal expansion or rodent activity can reopen old leaks. Re-testing every 5 years is recommended for long-term performance.
A family in Denver had high winter heating bills despite regular furnace maintenance. An energy audit revealed 34% duct leakage in the basement and attic. The ducts were inaccessible due to insulation and framing.
A certified Aeroseal technician conducted a pre-test, measuring 120 CFM (cubic feet per minute) of air loss. The system was set to 15 psi pressure. Over 90 minutes, the sealant circulated and sealed 117 out of 120 CFM of leakage.
Post-treatment testing showed 6 CFM of residual leakage-well below the 10% threshold recommended by ASHRAE. The family saw a 19% reduction in gas usage over the next heating season. They also reported more consistent room temperatures and fewer drafts.
I've seen this work firsthand during a home energy retrofit project. The house had fiberglass ducts with visible gaps around joints. After Aeroseal, the blower door test confirmed a 92% reduction in air infiltration. The client noted immediate improvements in comfort and quietness.
Traditional duct sealing relies on mastic paste, metal tape, or aerosol sprays applied manually. These methods require direct access to joints and are prone to human error. Mastic can crack over time; tape can peel off. Aerosol sprays often miss hidden leaks.
Aeroseal outperforms these techniques in coverage and durability. A 2021 study by the National Renewable Energy Laboratory found that Aeroseal reduced leakage by 94% on average, compared to 68% for manual mastic application. The study also noted that Aeroseal-treated systems maintained performance over five years, while manually sealed systems degraded by 15-20% annually.
Cost-wise, Aeroseal ranges from $1,200 to $2,500 depending on home size and system complexity. This compares to $800-$1,800 for manual sealing. However, Aeroseal's higher upfront cost is offset by greater energy savings and longer lifespan.
What is Aeroseal duct sealing? It's a targeted, automated solution that improves HVAC efficiency by sealing leaks from within. It's ideal for homes where access is limited, or where traditional methods fail to achieve consistent results. The process is safe, effective, and backed by independent research.
If you're considering sealing your ducts, a short look at flex duct can help you understand the materials involved. But for maximum impact, especially in older homes, Aeroseal offers a proven upgrade path to better comfort and lower utility bills.