Understanding Energy Codes and the Role of Air Barriers in Building Performance

Updated October 2026: This article has been revised with updated information and content.

Closing the Gaps: How Air Barriers Help Buildings Meet Today’s Energy Codes

Energy codes continue to raise expectations for building envelope performance. For architects, engineers and contractors, meeting those requirements increasingly depends on controlling one of the less visible sources of energy loss: uncontrolled air movement through the building envelope.

Air barriers help address this problem by limiting air infiltration and exfiltration through walls, roofs and other parts of the building enclosure. As energy codes have evolved, requirements for air barrier continuity, documentation and whole-building air leakage testing have become more stringent.

The 2024 International Energy Conservation Code (IECC) continues that progression, with updated commercial requirements that place greater emphasis on measurable building envelope performance.

Why Energy Codes Matter for Building Performance

Energy codes establish minimum requirements for the energy-efficient design and construction of buildings. For commercial construction, two important references are the  International Energy Conservation Code and ANSI/ASHRAE/IES Standard 90.1.

The IECC is updated on a three-year cycle and includes commercial building provisions. ASHRAE 90.1 also establishes minimum energy-efficiency requirements for commercial buildings.

Both address the building envelope as part of a broader strategy to reduce energy consumption. Insulation limits conductive heat flow, while air barriers reduce uncontrolled air movement. The effectiveness of each depends on continuity across the building envelope.

Air Leakage and Energy Performance in Commercial Buildings

Air can move through gaps in the building envelope due to wind, stack effect and mechanical pressure. Common leakage points include penetrations, joints, roof-to-wall transitions, window-to-wall transitions and connections between different materials.

When conditioned air escapes or outside air enters through these gaps, HVAC systems must compensate. Air leakage can also transport moisture into wall assemblies, potentially affecting durability and indoor environmental conditions.

A continuous air barrier addresses these pathways by creating an uninterrupted plane around the conditioned space. This makes air barrier design a system issue rather than simply a product specification. A membrane may meet required material standards, but the building can still leak if transitions and penetrations are not properly designed and installed.

What Changed in the 2024 IECC for Commercial Air Barriers?

The 2024 IECC Commercial Provisions continue the industry's move toward verified building envelope performance.

Section C402.6 addresses air leakage through the building thermal envelope, while Section C402.6.1 addresses air barriers. The code requires a continuous air barrier throughout the building thermal envelope, subject to specified exceptions.

One significant change involves whole-building air leakage. Under the 2024 IECC, the general maximum measured air leakage rate is 0.35 cfm/ft² of building thermal envelope area at 75 Pa, compared with 0.40 cfm/ft² under the previous code.

The 2024 IECC also includes provisions for buildings that exceed the target. When measured leakage is greater than 0.35 but does not exceed 0.45 cfm/ft², diagnostic evaluation can be used to locate leakage and identified leaks must be sealed where accessible. Specific testing requirements and exceptions also apply based on building conditions.

The updated code also places greater emphasis on identifying the air barrier and air-sealing details in construction documents. This reinforces the importance of addressing continuity during design and coordinating air barrier installation among trades.

Understanding Regional Energy Code Adoption and Compliance

The latest model energy code is not necessarily the code governing a particular project. States and local jurisdictions adopt model codes on different schedules and may modify them with local amendments.

As a result, design teams should determine the applicable energy code and climate zone early in the project. These requirements can influence insulation, air barrier design, vapor control, testing and other aspects of the building envelope.

Different Types of Air Barriers

There is no single air barrier system appropriate for every commercial building. Substrate, wall design, climate, construction sequencing and installation conditions can influence product selection.

Common air barrier types include:

• Self-adhered sheet air barriers, which use a factory-applied adhesive to bond the membrane to the substrate. Factory-controlled membrane thickness provides consistent coverage, while seams, penetrations and transitions are detailed to maintain continuity.
• Fluid-applied air barriers, which are applied directly to the substrate and can readily conform to irregular surfaces and complex geometries. Application thickness and substrate conditions must be controlled according to manufacturer requirements.
• Mechanically attached membranes, which are secured to the substrate with fasteners. Seams, penetrations and attachment points require careful detailing.
• Rigid materials and sheathing systems, which can serve as part of the air barrier when the materials and joints meet applicable air leakage requirements.

Compatibility with adjacent materials, substrate preparation and installation conditions should be considered along with the type of membrane selected.

Why Self-Adhered and Primerless AVBs Are Gaining Attention

Self-adhered air and vapor barriers (AVBs) have long been used in commercial wall assemblies because they combine controlled membrane thickness with full adhesion to the substrate. Unlike fluid-applied products, sheet membranes arrive at the jobsite at their specified thickness and create a visible control layer that can be inspected as work progresses.

Traditional self-adhered membranes may require primer before installation depending on the membrane and substrate. Primer adds material, application and drying steps to the installation process.

Primerless self-adhered AVBs eliminate that step on approved substrates. This can reduce material handling and simplify installation while retaining the benefits of a fully adhered sheet membrane.

Henry® has continued to advance self-adhered air barrier technology with Henry® Blueskin® SA HPX, a primerless, self-adhered air, vapor and water-resistive barrier for commercial wall assemblies. Its pressure-sensitive adhesive provides full adhesion to many common building substrates without primer and can be installed at temperatures as low as 0°F (-17.8°C).

Blueskin SA HPX is one option within a broader range of Henry air barrier technologies, including vapor-permeable self-adhered membranes and fluid-applied air barriers. This range gives design teams options for different wall assemblies, vapor profiles and installation conditions.

For a closer look at primerless technology and its role in self-adhered air barrier installation, see (link to blogs 1 and 2 Next Gen Primerless Air Barriers to Know and Blueskin® SA HPX: Beyond Primerless Installation)

Stricter whole-building air leakage requirements increase the importance of planning for testing before construction is complete. Waiting until final testing to identify leaks can make corrections more difficult once the air barrier is concealed by insulation, cladding or interior finishes.

Air barrier drawings should clearly identify the continuous control layer and show the tie-ins at walls, roofs, foundations, windows, doors and penetrations. Product compatibility should be confirmed, and installers should understand detailing requirements before installation begins.

Mockups, field observations and interim testing can help identify potential problems while the air barrier remains accessible.

Preparing for More Stringent Energy Codes

Energy codes increasingly focus on the performance of the building envelope as a complete system. For architects and engineers, that means considering air barrier continuity early in enclosure design. For contractors, it places greater emphasis on sequencing, substrate preparation and coordination among trades.

The membrane, accessories, transitions and installation details must work together to create a continuous air barrier from the foundation through the walls and into the roof assembly.

As jurisdictions adopt newer energy codes, understanding current requirements and available air barrier technologies will become increasingly important. Selecting the appropriate system and planning for continuity from design through installation can help project teams meet energy code requirements while supporting long-term building envelope performance.

For additional information about self-adhered, primerless and fluid-applied air barrier systems, visit Henry Building Envelope Systems.

Schedule a meeting today to see how Henry’s complete portfolio of solutions can help you achieve energy-code compliance and high-performance results.