Understanding the AeroBarrier Air-Sealing System
Meeting code-required airtightness levels has become one of the more challenging aspects of modern residential construction. Building codes across North America increasingly mandate strict air leakage limits, typically expressed as air changes per hour at 50 Pascals (ACH50). For many builders, reaching these targets using traditional methods such as caulking, gaskets, and spray foam requires meticulous attention to every joint, penetration, and seam in the building envelope. One technology that has emerged as a faster and more reliable alternative is the AeroBarrier system, an atomized sealant approach that can bring a house to required airtightness levels in a matter of hours.
Developed at the University of California, Davis, and commercialized in 2013, AeroBarrier uses a water-based acrylic sealant that is atomized into microscopic particles and forced into the building envelope under pressure created by a blower door. As the sealant particles travel through the air, they naturally find and seal gaps and cracks up to half an inch wide. The result is a uniform, measurable improvement in airtightness without the labor-intensive process of manually locating and sealing every individual leak. This approach represents a fundamental shift in how builders approach comprehensive air sealing in new construction.
The system is currently used almost exclusively in new single-family and multi-family residential projects. The ideal time to apply AeroBarrier is after drywall installation but before interior trim and cabinetry are fitted. At this stage, the building envelope is largely complete, but interior finishes have not yet been installed, making it straightforward to protect surfaces from overspray. Retrofitting existing homes is more challenging because of the labor required to protect furnishings and finished surfaces from the sealant mist.
How the AeroBarrier Process Works
Site Preparation and Protection
Before the AeroBarrier equipment arrives, the building must be prepared. All openings that should not be sealed, such as HVAC registers, plumbing vents, and intentional combustion air inlets, must be temporarily covered. Windows and doors are protected with plastic sheeting and tape. The process is similar to preparing a home for spray foam insulation, though the atomized particles are much finer and can travel farther, making thorough protection essential.
Equipment Setup and Sealant Application
The core of the system is a specialized machine that atomizes the water-based acrylic sealant and injects it into the building interior. A calibrated blower door creates negative pressure inside the house, drawing outside air in through every gap and crack in the envelope. The atomized sealant particles are carried by this airflow and deposit on the edges of the gaps, gradually building up a layer that closes the opening.
The key steps in the process include:
- Setting up the atomization machine and blower door in a central location within the building
- Sealing all intentional openings with temporary covers or tape
- Running the blower door to establish the target pressure differential
- Injecting the atomized sealant in controlled increments
- Monitoring real-time airtightness measurements as the sealant builds up on gaps
- Continuing the process until the target ACH50 is achieved
Real-Time Monitoring and Verification
One of the most significant advantages of the AeroBarrier system is that it provides immediate, measurable feedback. The blower door instrumentation continuously measures the building’s air leakage rate throughout the process. The operator can see exactly how much the airtightness improves with each pass of sealant application. This eliminates the guesswork inherent in traditional air sealing, where the effectiveness of the work is only known when a blower door test is performed at the end of the construction process.
Comparative Advantages Over Traditional Air Sealing Methods
Traditional air sealing relies on a combination of methods: caulking around window and door frames, applying gaskets under bottom plates, sealing electrical and plumbing penetrations with foam, and taping sheathing joints. While these methods can achieve excellent results when executed meticulously, they are labor-intensive and highly dependent on the skill and attention of individual tradespeople.
The table below compares AeroBarrier with conventional air sealing approaches across several performance criteria:
| Criteria | Traditional Air Sealing | AeroBarrier System |
|---|---|---|
| Labor requirement | High: multiple trades, multiple visits | Low: single crew, single visit |
| Time to complete | Days to weeks across multiple phases | 2 to 4 hours for typical home |
| Quality assurance | Visual inspection only; unknown until final test | Real-time measurement throughout process |
| Maximum gap sealed | Any size (manual sealing of all gaps) | Up to 1/2 inch per application pass |
| Material cost | Variable: caulk, foam, tape, gaskets | Higher per-project material cost |
| Labor cost savings | Baseline | Significant: offsets higher material cost |
| Predictability of result | Variable depending on workmanship | Consistent and adjustable in real time |
For builders who are already achieving 3 ACH50 through conventional methods, AeroBarrier offers the opportunity to reach the same or better airtightness with significantly less coordination among trades. The system is particularly valuable when paired with air barrier systems as part of a comprehensive building envelope strategy.
Value Engineering Through HERS Optimization
One of the more sophisticated applications of AeroBarrier involves leveraging the HERS (Home Energy Rating System) index for value engineering. A HERS score analyzes a home’s energy performance compared to a reference house built to the 2006 International Energy Conservation Code, which is assigned a score of 100. The lower the score, the better the home’s performance.
When a builder uses AeroBarrier to achieve very low air leakage reliably, the HERS model credits that airtightness improvement. This credit can be traded against other building components, allowing the builder to specify less expensive windows, reduced insulation levels, or simpler HVAC systems while still meeting the overall energy performance target set by code. The trade-off calculation is precisely quantifiable, making it a powerful tool for cost optimization.
The key trade-off opportunities include:
- Reducing window specification from triple-pane to high-performance double-pane units
- Decreasing exterior rigid foam insulation thickness while maintaining thermal performance
- Sizing HVAC equipment more precisely to the reduced heating and cooling load
- Simplifying air sealing details at difficult junctions where manual sealing is expensive
Practical Considerations for Implementation
When to Schedule AeroBarrier in the Construction Sequence
The most common and effective time to apply AeroBarrier is after drywall is installed and taped but before interior trim, cabinets, and flooring are fitted. At this stage, the building envelope is complete, and the interior surfaces that need protection are still relatively easy to cover. The sequence typically follows this order:
- Rough-in inspections completed
- Insulation installed in all exterior wall cavities
- Drywall hung, taped, and finished
- Interior doors hung but not trimmed
- AeroBarrier application performed
- Trim, cabinets, flooring, and final finishes installed
Limitations and Site Suitability
AeroBarrier is not a universal solution. The system cannot seal gaps larger than half an inch in a single pass, which means large bypasses and structural gaps must be addressed with traditional methods before the AeroBarrier crew arrives. The system also works best in new construction; existing occupied homes present significant challenges because of the difficulty of protecting furnishings and finishes from the atomized sealant mist.
The most suitable project types for AeroBarrier include:
- New single-family homes targeting ENERGY STAR or Passive House certification
- Multi-family residential buildings where consistent airtightness across units is critical
- Projects where construction schedules are tight and air sealing is on the critical path
- Buildings with complex geometries where traditional air sealing is particularly labor-intensive
Understanding how AeroBarrier integrates with other envelope components is essential for successful implementation. Builders should review their building envelope design to ensure the system complements the overall moisture management and thermal control strategy rather than conflicting with it.
Verification and Code Compliance
AeroBarrier provides continuous, documented measurement of airtightness improvement throughout the application process. The system generates a final report showing the starting and ending ACH50 values, the total amount of sealant applied, and the time taken to reach the target. This documentation serves as built-in code compliance evidence for jurisdictions that require blower door testing as part of their energy code enforcement.
Builders using AeroBarrier typically schedule a third-party blower door test for final code verification as well, since most energy codes require independent testing. However, the pre-test data from the AeroBarrier process provides a high degree of confidence that the home will pass before the official test is conducted. This predictability eliminates the costly scenario of failing a blower door test and having to mobilize a crew to locate and seal remaining leaks. For more on verification methods, see air leakage testing procedures for building envelopes.
Cost Analysis and Return on Investment
The cost of AeroBarrier varies by market and project complexity, but typical pricing for a single-family home ranges from $2,000 to $4,000. When evaluated against the combined cost of traditional air sealing materials, the labor for multiple trades to execute air sealing details, and the risk of failing a blower door test, the system often proves cost-neutral or cost-positive for production builders.
The value proposition strengthens significantly when the HERS trade-off opportunities are included. A builder who can specify less expensive windows or reduce insulation thickness while maintaining energy code compliance may save thousands of dollars per home, far exceeding the cost of the AeroBarrier application itself.
For custom home builders and owners pursuing high-performance certifications such as Passive House or net-zero energy, AeroBarrier provides a reliable path to the very low airtightness levels these programs require. Achieving 0.6 ACH50 or better for Passive House certification is challenging with manual air sealing alone, but AeroBarrier makes these targets consistently achievable.