HERS Rater Certification Requirements

Last updated: April 2026

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Quick Answer

The 2024 International Energy Conservation Code (IECC) is the latest model energy code, updated every 3 years by the International Code Council (ICC).
The U.S. Department of Energy (DOE) determined the 2024 IECC achieves 7.8% site energy savings and 6.6% energy cost savings compared to the 2021 IECC.
This new code offers more flexibility for builders to meet compliance targets in residential provisions, despite having more challenging overall energy performance targets.
Key changes for residential buildings include a reduction in prescriptive attic insulation requirements by R-11 across all climate zones.

The 2024 International Energy Conservation Code (IECC) is a crucial update for anyone involved in home energy efficiency, especially HERS Raters. This model building code, developed by the International Code Council (ICC), sets the minimum efficiency standards for new construction. It covers vital components like walls, floors, ceilings, lighting, windows, doors, and critical aspects such as duct leakage and air leakage in homes. The IECC, first established in 2000, is the most widely adopted energy code in the United States, serving as the national model for low-rise residential buildings. The U.S. Department of Energy (DOE) has confirmed that the 2024 IECC achieves a 7.8% site energy savings and a 6.6% energy cost savings when compared to its predecessor, the 2021 IECC. For HERS Raters and other energy code professionals, understanding these updates is essential. The 2024 IECC will become the standard benchmark for numerous states, counties, and municipalities, shaping how new homes are built and rated for energy performance.

What is the 2024 IECC and Why Does It Matter for HERS Raters?

The 2024 International Energy Conservation Code (IECC) represents the latest iteration of a foundational model building code created by the International Code Council (ICC). This code is designed to establish minimum energy efficiency standards for new construction projects across the United States. It specifies requirements for various building components that directly impact a home's energy use, including the thermal performance of walls, floors, and ceilings. Beyond the building envelope, the IECC also addresses the efficiency of lighting systems, windows, and doors. Crucially, it sets standards for critical air sealing measures such as duct leakage and overall building air leakage, which are significant factors in a home's energy consumption.

The IECC holds a significant position in the construction industry because it is the most widely adopted energy code in the country. It serves as the national model energy code, particularly for low-rise residential buildings, influencing how homes are designed and constructed to save energy. The code, first created in 2000, undergoes regular updates every three years. This triennial revision process ensures that the IECC stays current with advancements in building science, technology, and energy efficiency goals. The release of the 2024 edition means that new, more stringent, yet often more flexible, standards are now available for adoption by local jurisdictions.

For HERS (Home Energy Rating System) Raters and other energy code professionals, comprehending the specifics of the 2024 IECC updates is not merely beneficial, but absolutely vital. The IECC 2024 will serve as the benchmark for a growing number of states, counties, and municipalities moving forward. This means that the criteria HERS Raters use to evaluate and certify a home's energy performance will be directly influenced by the provisions of this new code. HERS Raters are responsible for performing detailed home energy audits, modeling energy performance, and verifying compliance with energy codes and programs. Therefore, an intimate knowledge of the 2024 IECC's requirements is indispensable for accurately assessing homes, guiding builders, and ensuring that new construction meets the latest efficiency standards. Without this understanding, HERS Raters would struggle to provide accurate ratings, identify areas for improvement, or help builders achieve compliance. The code’s influence extends to various aspects of building design and construction, from the R-values of insulation to the air tightness targets, all of which fall under the purview of a HERS Rater’s assessment.

The Role of the International Code Council (ICC)

The International Code Council (ICC) is the organization responsible for developing the IECC. The ICC is a member-focused association dedicated to developing model codes and standards used in the design, build, and compliance process to construct safe, sustainable, affordable, and resilient structures. Their work on the IECC provides a uniform set of guidelines that can be adopted by jurisdictions nationwide. This standardization helps ensure a baseline level of energy performance across different regions, though local amendments can tailor the code to specific climatic or regional needs. The ICC's process involves extensive input from industry experts, builders, and energy professionals to create a code that is both effective and practical for implementation.

Why Regular Updates are Essential

The triennial update cycle of the IECC is critical for several reasons. Building technology, materials, and understanding of energy dynamics in homes evolve rapidly. Regular updates allow the code to integrate the latest innovations and best practices. For example, as insulation materials improve, or as new methods for air sealing become more efficient, the IECC can reflect these advancements. These updates also help to push the envelope of energy efficiency, gradually leading to more sustainable building practices and reduced energy consumption across the housing sector. Each new edition aims to achieve incrementally higher energy savings, contributing to broader environmental and economic goals. The 2024 IECC, for instance, builds upon the foundations of earlier versions, integrating feedback and new research to refine its provisions and enhance its impact on energy conservation.

How Does the 2024 IECC Improve Energy Efficiency?

The 2024 International Energy Conservation Code (IECC) significantly improves energy efficiency by setting more challenging performance targets while simultaneously offering increased flexibility in how those targets can be met. The U.S. Department of Energy (DOE) conducted a thorough analysis of the new code. This analysis concluded that the 2024 IECC achieves a substantial 7.8% site energy savings and a 6.6% energy cost savings when compared to the previous edition, the 2021 IECC. These figures highlight the tangible benefits of adopting the updated code, translating directly into reduced energy consumption and lower utility bills for homeowners.

The improvements in energy efficiency are not solely about stricter requirements. A key feature of the 2024 IECC, particularly within its residential provisions, is the enhanced flexibility it provides to builders. This means that while the overall energy performance targets have indeed become more challenging, builders now have a wider range of options and pathways to achieve compliance. This flexibility is crucial for practical implementation in the field, allowing builders to choose methods and materials that best suit their designs, local availability, and cost-effectiveness without compromising the ultimate energy efficiency goal. This approach recognizes that a "one-size-fits-all" solution may not always be optimal and empowers builders to innovate within the framework of the code.

The 2024 IECC serves as the fundamental basis for numerous state and city energy codes across the nation. When a jurisdiction adopts the IECC 2024, either with or without local amendments, it establishes a new minimum standard for energy-efficient construction within that area. This widespread adoption mechanism ensures that the energy savings determined by the DOE can be realized on a broad scale. The code's robust framework provides a consistent, science-backed approach to energy efficiency that local governments can implement to drive down energy consumption in new buildings. The commitment to higher energy performance targets, coupled with practical flexibility, makes the 2024 IECC a powerful tool for advancing energy conservation in residential construction.

Specifics of Energy Savings

The determination by the U.S. Department of Energy (DOE) regarding the 2024 IECC's energy savings is a critical piece of information for all stakeholders. Nathan Kahre, Sr. Program Manager, Codes & Standards at NAHB, noted that "The U.S. Department of Energy (DOE) issued a determination on the 2024 IECC showing that it achieves a 7.8% site energy savings and 6.6% energy cost savings compared to the previous edition, the 2021 IECC" (from U.S. Department of Energy 2024 IECC determination). Site energy savings refer to the actual energy consumed at the building site, while energy cost savings reflect the reduction in utility expenses. These figures are significant because they demonstrate a measurable improvement over the prior code, reinforcing the value of adopting the 2024 IECC. This improvement is achieved through a combination of factors, including updated requirements for insulation, windows, HVAC systems, and air sealing.

Balancing Stringency with Flexibility

The balance between making energy performance targets more challenging and providing greater flexibility is a hallmark of the 2024 IECC. This approach acknowledges the diverse challenges faced by builders across different climate zones and market conditions. Rather than imposing a rigid set of prescriptive requirements for every single component, the new code often allows for trade-offs. For example, a builder might choose to exceed insulation requirements in one area if it allows for a slightly different approach in another, provided the overall energy performance of the home meets or exceeds the code's target. This performance-based approach encourages innovation and allows builders to optimize their designs for efficiency in a way that is also cost-effective and practical. This flexibility is a direct result of ongoing collaboration and feedback from industry professionals, including builders and energy experts, who work to ensure the code's provisions are implementable in the real world.

What Are the Key Residential Updates in the 2024 IECC?

The 2024 International Energy Conservation Code (IECC) brings many important updates for residential buildings, moving beyond the 2021 IECC with new requirements and increased flexibility. While the overall goal is to make homes more energy-efficient, some specific changes stand out as particularly impactful for builders and HERS Raters. These updates cover various aspects of a home's energy performance, from the building envelope to mechanical systems, aiming for higher efficiency standards across the board.

One of the most significant changes noted in the 2024 IECC relates to ceiling insulation requirements. The prescriptive attic insulation requirements have been reduced by R-11 across all climate zones. This change might seem counterintuitive at first glance, given the general trend towards increased efficiency. However, it reflects a broader strategy within the 2024 IECC to provide more flexibility and a wider range of options for builders to achieve overall compliance. Instead of rigid, component-specific requirements, the code often allows for performance-based compliance, where trade-offs can be made as long as the total energy performance target is met. This means that while attic insulation might be reduced in some prescriptive paths, other elements of the home's design or construction must compensate to ensure the overall energy performance still achieves the new, more challenging targets. This shift encourages a holistic view of a home's energy efficiency, rather than focusing solely on individual components.

Beyond insulation, the 2024 IECC includes updates across various residential energy efficiency categories. These changes are designed to push the industry towards more sustainable building practices and lower energy consumption in new homes. For example, updates might include enhanced requirements for window U-factors and solar heat gain coefficients (SHGC), improved air leakage targets for the building envelope, or more efficient mechanical ventilation systems. The code also delves into aspects like water heating, lighting, and even the infrastructure for future energy technologies such as electric vehicle charging and renewable energy systems. Each of these updates contributes to the overarching goal of creating homes that are not only more comfortable but also significantly more energy-efficient and environmentally friendly. HERS Raters must be fully aware of these specific changes because they directly impact the calculations and verifications performed during a home energy rating. Understanding these nuances allows them to accurately guide builders and ensure compliance with the latest standards.

Changes in the Building Envelope

The building envelope—which includes the roof, walls, windows, and foundation—is crucial for a home's energy performance. The 2024 IECC introduces several modifications to how this envelope must be constructed to minimize heat loss in winter and heat gain in summer. While the reduction in prescriptive attic insulation by R-11 is a notable change, it's essential to understand it within the context of the code's new performance-based pathways. Builders might achieve compliance by investing more in high-performance windows, superior wall insulation, or exceptionally tight air sealing, rather than relying solely on maximum attic insulation. This approach provides design flexibility, allowing builders to optimize their material choices and construction techniques while still delivering an energy-efficient home. For example, a home in a specific climate zone might achieve compliance by combining slightly less attic insulation with advanced framing techniques and superior wall insulation, which collectively meet the overall energy performance target.

Air Leakage and Ventilation Updates

Air leakage is a major contributor to energy waste in homes. The 2024 IECC continues to emphasize the importance of a tightly sealed building envelope. While the specific numerical targets for air changes per hour (ACH) might be adjusted or refined, the overall trend is towards more stringent requirements for air sealing. This means that builders will need to implement robust air barrier strategies and conduct thorough blower door tests to verify compliance. HERS Raters play a critical role here, performing these tests and identifying areas where air leakage needs to be addressed. Furthermore, as homes become tighter, mechanical ventilation becomes even more important to ensure good indoor air quality. The 2024 IECC likely includes updates to ventilation requirements, ensuring that homes remain healthy and comfortable even as their envelopes become more airtight. These updates might specify minimum ventilation rates or require the use of energy recovery ventilators (ERVs) or heat recovery ventilators (HRVs) in certain climate zones to minimize energy loss from ventilation.

Integration with Other Efficiency Initiatives

The updates in the 2024 IECC are not developed in isolation. They are designed to align with and support other key energy efficiency initiatives. For instance, the new code’s provisions can directly impact a home’s eligibility for programs like ENERGY STAR certification or specific HUD loan qualifications. A home built to the 2024 IECC standards will inherently be closer to meeting the requirements for these programs, which often build upon the base energy code requirements. This synergy between the model energy code and voluntary certification programs helps to streamline the process for builders seeking to achieve multiple efficiency benchmarks. The interaction between IECC 2024 and these programs presents both new opportunities and challenges for the building industry, requiring careful attention from HERS Raters and energy professionals to ensure homes meet all relevant criteria. The code provides the foundation, and programs like ENERGY STAR build upon it, offering pathways to even higher levels of energy performance and recognition.

Which Jurisdictions Are Adopting the 2024 IECC?

The 2024 International Energy Conservation Code (IECC) is a model building code, meaning it is not automatically enforced nationwide. Instead, it serves as a template that individual states, counties, and municipalities can choose to adopt. Many jurisdictions across the United States are in the process of reviewing and adopting the IECC 2024, recognizing its role as the industry standard for energy codes. This adoption process can take different forms: some jurisdictions may adopt the code verbatim, while others may choose to implement it with specific local amendments that tailor the code to their unique climate, economic conditions, or policy goals.

The IECC 2024, when combined with these local jurisdiction amendments, effectively forms the state and city energy codes that builders and HERS Raters must follow. This means that the specific requirements for energy efficiency can vary slightly from one region to another, even if both are based on the 2024 IECC. It is crucial for professionals to not only understand the core provisions of the 2024 IECC but also to be aware of any local modifications that apply to their specific working area.

Several jurisdictions have already adopted or are in the process of adopting the 2024 IECC. These adopting jurisdictions include prominent cities and states such as Phoenix, Arizona; Colorado; Illinois; Nevada; Clark County, Nevada; Las Vegas, Nevada; New York State; New York City; North Dakota; Rhode Island; Nashville and Davidson County, Tennessee; Austin, Texas; and Utah. This list demonstrates a broad geographical interest in implementing the latest energy efficiency standards. For example, both Colorado and Utah are noted as adopting the IECC 2024 with amendments, indicating their intent to customize the code to their specific needs. This widespread adoption underscores the importance of the 2024 IECC as the evolving benchmark for energy performance in new construction across a significant portion of the country. HERS Raters working in these areas must be intimately familiar with both the national model code and any local variations to ensure accurate ratings and compliance verification.

The Adoption Process

The process of adopting a new energy code typically involves legislative or regulatory action at the state or local level. This can include public hearings, reviews by building code councils, and eventual passage into law or regulation. Jurisdictions often consider factors such as climate, energy costs, and the economic impact on builders and homeowners when deciding whether to adopt the latest IECC and what amendments to include. Some states may have a statewide energy code, while others allow individual cities or counties to adopt their own versions. This decentralized approach means that HERS Raters often need to track multiple sets of regulations depending on their service area. Understanding the specifics of each jurisdiction's adoption status and any amendments is paramount for ensuring compliance and providing accurate energy ratings.

Impact of Amendments

The inclusion of amendments by jurisdictions is a key aspect of the IECC adoption process. These amendments can either strengthen the code's requirements, relax certain provisions, or add entirely new sections to address local priorities. For instance, a jurisdiction might add stricter requirements for renewable energy readiness or specific insulation levels beyond the IECC's base provisions. Conversely, an amendment might offer alternative compliance pathways to accommodate local building practices or material availability. This variability means that while the 2024 IECC provides a common foundation, the practical application of the code can differ. For example, Energy Code, 2024 (IECC 2024) | UpCodes lists Colorado and Utah as adopting the code "With Amendments." HERS Raters must consult the specific energy code documents for each jurisdiction where they operate to ensure they are applying the correct standards. Relying solely on the national model code without checking for local amendments could lead to non-compliance or inaccurate energy ratings. This detailed understanding is what distinguishes an effective HERS Rater in a diverse regulatory landscape.

How Does the 2024 IECC Relate to ENERGY STAR and HUD Loan Qualifications?

The 2024 International Energy Conservation Code (IECC) has a direct and significant relationship with key energy efficiency initiatives, including the ENERGY STAR Residential New Construction Program and qualifications for HUD-backed loans. These programs often build upon the foundational requirements set by the energy code, aiming for even higher levels of energy performance. Therefore, understanding the 2024 IECC is critical for builders and HERS Raters looking to achieve these additional certifications and benefits.

The 2024 IECC's updated standards for building envelope performance, air leakage, and mechanical system efficiency directly influence whether a new home can qualify for the ENERGY STAR Residential New Construction Program. ENERGY STAR, a program of the U.S. Environmental Protection Agency, certifies homes and apartments that are significantly more energy-efficient than those built to minimum code standards. To earn the ENERGY STAR label, a home must meet rigorous guidelines for energy efficiency set by the program. While the IECC provides the baseline, ENERGY STAR requirements often necessitate exceeding these minimums in various aspects, such as tighter air sealing, higher insulation values, or more efficient HVAC systems. When a home is built to the 2024 IECC, it already incorporates many of the best practices that align with ENERGY STAR goals, making the path to certification smoother. The program emphasizes a comprehensive, whole-house approach to energy efficiency, which complements the performance-based compliance options now more prevalent in the 2024 IECC.

Similarly, the energy performance standards outlined in the 2024 IECC can affect eligibility for certain HUD loan qualifications. The U.S. Department of Housing and Urban Development (HUD) offers various loan programs, some of which provide incentives or require specific energy efficiency levels for new construction. These requirements are often tied to recognized energy codes or certifications. A home that meets or exceeds the 2024 IECC standards is generally in a better position to satisfy any energy efficiency prerequisites for HUD-backed financing. This connection underscores the economic benefits of building to higher energy codes, as it can expand financing options for homebuyers and incentivize builders to adopt more efficient practices. The IECC acts as a foundational layer, and programs like ENERGY STAR and HUD loan qualifications represent higher tiers of energy performance that are increasingly sought after by consumers and policy makers. HERS Raters play a pivotal role in verifying that homes meet both the mandatory code requirements and the voluntary program standards.

The ENERGY STAR Residential New Construction Program

The ENERGY STAR Residential New Construction Program is a voluntary program designed to promote the construction of homes that are substantially more energy-efficient than standard code-built homes. ENERGY STAR certified new homes are verified by a third-party Rater to be at least 10% more efficient than homes built to code and include additional measures that deliver a total energy efficiency improvement of 20% or more. The program’s requirements are detailed in documents like the Single-Family Program Requirements and the broader ENERGY STAR Residential New Construction Program information. These homes are designed to deliver better quality, better comfort, and better durability for homeowners. For example, a home built to 2024 IECC standards might meet the basic insulation and air sealing requirements, but to achieve ENERGY STAR certification, it might need even tighter ductwork, more efficient windows, or specific high-efficiency appliances. HERS Raters are essential partners in this program, conducting the necessary inspections and tests to ensure homes meet the stringent ENERGY STAR criteria.

HUD Loan Qualifications and Energy Efficiency

HUD-backed loans, such as FHA loans, can be crucial for homebuyers. While not every HUD loan directly mandates a specific energy code, there is a growing emphasis on energy efficiency in housing policies. Homes that are built to higher energy standards, like those established by the 2024 IECC, are generally seen as more valuable and less costly to operate over time. This makes them more attractive for lenders and potentially qualifies them for favorable loan terms or specific green financing options that HUD might support. The connection between the IECC and HUD requirements highlights how energy codes contribute to broader housing affordability and sustainability goals. By ensuring homes are built to the latest efficiency standards, HERS Raters help facilitate access to these financial benefits for homeowners, reducing their long-term cost of ownership through lower energy bills. This integration of energy codes into financial incentives demonstrates a holistic approach to promoting energy-efficient construction.

What Does This Mean for HERS Rater Certification?

For HERS Raters, the release and adoption of the 2024 International Energy Conservation Code (IECC) signifies a critical juncture in their professional development and daily practice. The dynamic nature of energy codes means that HERS Raters cannot rely on outdated knowledge; they must continuously update their expertise to remain effective and credible. The 2024 IECC will swiftly become the benchmark for energy performance in new residential construction across many states and localities, directly impacting the core responsibilities of a HERS Rater.

Staying current with the latest code updates is not just a recommendation; it is an absolute necessity for HERS Raters. Their primary role involves evaluating the energy performance of homes, often through detailed assessments and the use of sophisticated energy modeling software. These tools and methodologies are calibrated to the prevailing energy codes. If a Rater is unfamiliar with the specific provisions of the 2024 IECC, including its new performance targets, prescriptive requirements, and compliance pathways, they risk providing inaccurate ratings. This could lead to homes failing to meet code, builders facing costly rework, or homeowners missing out on potential energy savings and incentives. The updates require HERS Raters to understand how various building components interact under the new code, how to perform the necessary diagnostic tests (like blower door tests for air leakage and duct blaster tests for duct leakage), and how to accurately input data into their energy modeling software to reflect the 2024 IECC standards.

Understanding the new code ensures that HERS Raters can perform accurate home energy ratings and verify compliance effectively. The 2024 IECC, as highlighted by Overview of the 2024 IECC for Residential Construction, brings significant changes, such as the revised ceiling insulation requirements and the increased flexibility in meeting overall energy performance targets. HERS Raters must be adept at navigating these changes. This includes knowing when a prescriptive approach is applicable versus when a performance-based approach is required or preferred. They must also be able to communicate these complex code requirements clearly to builders, helping them choose the most effective and compliant construction methods. Ultimately, the competence of HERS Raters in applying the 2024 IECC directly supports the broader goals of energy conservation, carbon reduction, and the creation of more sustainable and affordable housing. Their expertise ensures that the intent of the code—to build smarter and more efficient homes—is realized in practice.

Training and Continuing Education

To meet the demands of the 2024 IECC, HERS Raters will likely need to engage in specialized training and continuing education. Certification bodies and industry organizations typically offer courses that cover the nuances of new code editions. These educational opportunities are crucial for understanding the technical specifics, such as updated R-values, U-factors, air leakage targets, and new sections related to renewable energy or electric vehicle infrastructure. Training also helps Raters understand the implications of the code's increased flexibility, particularly in how performance pathways allow for trade-offs among different energy-saving measures. Without this ongoing education, a Rater’s certification might not fully reflect their ability to work with the most current industry standards, potentially limiting their opportunities and effectiveness.

The Role of Software and Tools

Energy modeling software is an indispensable tool for HERS Raters. These programs simulate a home's energy performance based on various inputs, helping to determine compliance and identify areas for improvement. With the release of the 2024 IECC, software providers must update their platforms to incorporate the new code's specific algorithms, prescriptive tables, and performance targets. HERS Raters must ensure they are using the latest versions of their software, which are compliant with the 2024 IECC. Furthermore, Raters need to be proficient in using these updated tools, understanding how the new code parameters are integrated and how to accurately model homes against these standards. This includes understanding how changes like the reduction in prescriptive attic insulation by R-11 across all climate zones impact the overall energy model and how to account for compensatory measures taken elsewhere in the home's design. The accuracy of a HERS rating is directly tied to the Rater's ability to correctly apply the code through these advanced software tools.

Ensuring Market Competitiveness

Staying updated with the 2024 IECC also ensures a HERS Rater's market competitiveness. Builders and homeowners increasingly seek professionals who are knowledgeable about the latest standards and can help them achieve the highest levels of energy efficiency. A Rater who can confidently guide clients through the complexities of the 2024 IECC, explain its benefits, and help them achieve compliance or even surpass the code for programs like ENERGY STAR, will be highly valued. This proactive approach not only builds trust but also positions the Rater as a leading expert in the field. As the 2024 IECC becomes widely adopted, it will define the baseline for quality and efficiency in new construction, making knowledge of its provisions a non-negotiable aspect of professional competence for HERS Raters.

Frequently Asked Questions

What is the primary purpose of the IECC?

The primary purpose of the International Energy Conservation Code (IECC) is to set minimum energy efficiency standards for new construction. It covers various building components, including walls, floors, ceilings, lighting, windows, doors, duct leakage, and air leakage. The goal is to reduce energy consumption in buildings, thereby lowering energy costs and promoting sustainability. The IECC was first created in 2000 and has become the most widely adopted energy code in the United States.

How often is the International Energy Conservation Code updated?

The International Energy Conservation Code is updated every three years by the International Code Council (ICC). This regular update cycle ensures that the code remains current with advancements in building science, technology, and energy efficiency practices. The latest edition is the 2024 IECC, which builds upon the previous 2021 edition with new requirements and flexibilities.

What are the main energy savings attributed to the 2024 IECC?

The U.S. Department of Energy (DOE) determined that the 2024 IECC achieves significant energy savings compared to its predecessor. Specifically, it achieves a 7.8% site energy savings and a 6.6% energy cost savings when compared to the 2021 IECC. These savings represent the measurable improvements in energy performance that new homes built under the 2024 code are expected to achieve.

Did attic insulation requirements change in the 2024 IECC?

Yes, attic insulation requirements have changed in the 2024 IECC. The prescriptive attic insulation requirements have been reduced by R-11 across all climate zones. This change is part of the code's strategy to offer more flexibility to builders, allowing for a wider range of options to achieve overall energy performance targets rather than relying solely on rigid, component-specific requirements.

Which states have adopted the 2024 IECC?

Many states, counties, and municipalities are adopting the 2024 IECC, either with or without amendments. Adopting jurisdictions include Phoenix, Colorado, Illinois, Nevada, Clark County, Las Vegas, New York State, New York City, North Dakota, Rhode Island, Nashville and Davidson County, Austin, and Utah. This widespread adoption shows the code's growing influence as the national model for energy efficiency in new construction.