State Energy Code Adoption Tracker

Last updated: April 2026

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Quick Answer

The 2024 International Energy Conservation Code (IECC) is the newest model energy code from the International Code Council (ICC), updated every three years.
The U.S. Department of Energy (DOE) determined that the 2024 IECC achieves a 7.8% site energy savings and 6.6% energy cost savings compared to the previous 2021 edition.
States like Colorado and Utah have already adopted the 2024 IECC, often including their own amendments.
This code gives builders more flexibility to meet energy performance targets, even as those targets have become more challenging.

The 2024 International Energy Conservation Code (IECC) is the latest set of guidelines for energy efficiency in new buildings across the United States. Developed by the International Code Council (ICC) and updated every three years, this model code is crucial for setting minimum efficiency standards. It covers many parts of a new structure, including walls, floors, ceilings, lighting, windows, doors, and how much air or ductwork leaks. The U.S. Department of Energy (DOE) found that the 2024 IECC delivers significant improvements, achieving a 7.8% site energy savings and a 6.6% energy cost savings when compared to the 2021 IECC. This means new buildings built to the 2024 code will use less energy and cost less to operate. For us in the energy efficiency field, understanding these updates is key, as the IECC forms the basis for many state and local energy codes.

What is the 2024 IECC and Why Does it Matter?

The 2024 International Energy Conservation Code (IECC) is a model building code created by the International Code Council (ICC) that establishes minimum energy efficiency requirements for new construction. It matters because it directly influences how energy-efficient new homes and commercial buildings will be, setting standards for everything from insulation levels to window performance and air sealing. The IECC was first established in 2000, and since then, it has become the most widely adopted energy code in the country, recognized as the national model for low-rise residential buildings. We see this code as the foundational document that many states and cities use to create their own energy regulations.

The code is not a static document; the ICC updates it every three years to reflect advancements in building science and energy-saving technologies. For example, the 2024 edition builds on previous versions, pushing for greater efficiency. The U.S. Department of Energy (DOE) carefully reviewed the 2024 IECC and issued a determination stating that it achieves a 7.8% site energy savings when compared to the 2021 IECC. This means that buildings constructed under the 2024 code are expected to consume nearly 8% less energy at the building site than those built under the previous code. Beyond just energy use, the DOE also found that the 2024 IECC leads to a 6.6% energy cost savings compared to the 2021 edition. These savings translate directly into lower utility bills for homeowners and building occupants.

The importance of the IECC extends beyond just new construction. It also includes provisions for existing buildings, found in Chapter 5 [CE] for commercial structures and Chapter 5 [RE] for residential ones. This helps guide improvements in older buildings, ensuring that efficiency is considered during renovations and additions. The code is comprehensive, covering a broad range of building components and systems. It sets standards for a structure’s walls, floors, ceilings, lighting, windows, doors, duct leakage, and air leakage. Each of these elements plays a critical role in a building's overall energy performance. When we talk about air leakage, for instance, we are referring to uncontrolled air movement in and out of a building, which can lead to significant energy waste. The IECC sets strict limits to minimize this, requiring better sealing and construction practices.

The 2024 IECC also includes several appendices that address forward-looking energy concepts. For residential buildings, these appendices cover important areas like Appendix RB for solar-ready provisions in detached one- and two-family dwellings and townhouses. This means new homes can be built with the infrastructure to easily add solar panels later. Appendix RC discusses zero net energy residential building provisions, outlining paths for homes to produce as much energy as they consume over a year. Other appendices address electric vehicle charging infrastructure (Appendix RE) and electric-ready residential building provisions (Appendix RK), preparing homes for future energy demands and technologies. These additions show the code's focus on future-proofing buildings and promoting sustainable energy practices. The code's structure, with its clear chapters and detailed appendices, makes it a robust guide for builders, designers, and code officials. It is the industry standard for energy codes in the USA, and understanding its updates is very important to HERS Raters and energy code professionals, as it will be the benchmark for many states, counties, and municipalities moving forward.

The Role of the International Code Council (ICC)

The ICC is the organization behind the IECC. They develop a suite of model codes that jurisdictions across the country adopt to ensure public safety, health, and welfare in the built environment. The IECC is just one part of this larger family of codes, but it is a critical one for energy efficiency. The ICC’s process involves extensive input from various stakeholders, including builders, manufacturers, engineers, and energy experts. This collaborative approach helps create a code that is technically sound and practical for implementation.

Measuring Energy Savings: Site vs. Source

When the DOE talks about "site energy savings," they are referring to the energy consumed directly at the building itself, such as electricity, natural gas, or propane. "Energy cost savings" refers to the reduction in the total cost of energy bills. These metrics are important because they directly show the benefits to the building owner. For us, these numbers confirm the tangible value of adopting and complying with the latest energy codes. The DOE's determination acts as a strong endorsement of the 2024 IECC's effectiveness in promoting energy efficiency.

Why Codes Are Necessary

Energy codes like the IECC ensure a baseline level of energy performance for all new construction. Without these codes, builders might choose less efficient materials and practices to reduce upfront costs, which would lead to higher energy consumption and increased operational costs for homeowners over the life of the building. The IECC provides a level playing field and guarantees that new buildings meet a certain standard of efficiency, benefiting both the environment and consumers.

What are the Key Updates for Residential Buildings in the 2024 IECC?

The 2024 IECC brings important changes for residential buildings, introducing more challenging energy performance targets while also giving builders increased flexibility to meet these new standards. This balance is crucial because it allows for innovation in construction methods while still pushing for better energy efficiency. "Overall, the energy performance targets have gotten more challenging, but there is more flexibility in how to meet the targets," according to Ekotrope, an energy efficiency expert. This means we are seeing a shift towards outcome-based performance rather than just prescriptive requirements.

One of the most significant changes for residential provisions is the adjustment in prescriptive attic insulation requirements. The 2024 IECC has reduced the required attic insulation by R-11 across all climate zones. This change might seem counterintuitive at first glance, given the push for higher energy performance. However, it is part of a broader strategy to offer builders more options. This adjustment allows builders to optimize other parts of the building envelope or systems to achieve the overall energy performance targets, rather than being strictly limited by a single component's R-value. For example, a builder might invest in more efficient windows or advanced HVAC systems to compensate for the lower attic insulation, still meeting or exceeding the overall energy performance goals. This flexibility is a key aspect of the 2024 IECC, allowing builders to choose the most cost-effective and practical ways to comply, depending on their specific designs and regional conditions.

The residential section of the code is primarily found in Chapter 4 [RE], which focuses on residential energy efficiency. This chapter outlines specific requirements for various building components, including insulation, windows, doors, and air leakage. Chapter 5 [RE] then addresses existing residential buildings, providing guidance for energy efficiency improvements during renovations or additions. These chapters work together to ensure that both new and older homes contribute to overall energy savings. The code's structure helps users easily navigate between requirements for different building types and stages of construction.

Beyond the core chapters, the 2024 IECC includes several appendices that offer advanced options and provisions for residential buildings. Appendix RB, for instance, details solar-ready provisions for detached one- and two-family dwellings and townhouses. This means that the design of new homes should account for the future installation of solar energy systems, making it easier and less expensive for homeowners to add solar panels later. Appendix RC introduces zero net energy residential building provisions, providing a framework for homes that produce as much energy as they consume. These provisions are a significant step towards highly sustainable housing.

Other appendices address the growing demand for electric infrastructure. Appendix RE covers electric vehicle charging infrastructure, setting requirements for new homes to include the necessary wiring and capacity for EV chargers. Appendix RK provides electric-ready residential building provisions, ensuring that homes are designed to accommodate a future shift to all-electric appliances and systems. These forward-thinking additions prepare homes for a future with increased electrification and renewable energy integration. They help homeowners reduce their carbon footprint and take advantage of new technologies. The 2024 IECC Stretch Code, detailed in Appendix RG, offers jurisdictions an even higher level of energy efficiency to adopt if they choose, pushing the boundaries of current building practices. This stretch code can serve as a stepping stone for communities aiming for leadership in energy conservation. Finally, Appendix RH focuses on operational carbon rating and energy reporting, emphasizing the importance of tracking and understanding a building's actual energy performance and carbon footprint over its lifespan.

Flexibility in Compliance Paths

The 2024 IECC moves towards a more performance-based approach, giving builders more options for compliance. Instead of rigidly following a set of prescriptive requirements for every single component, builders can use a total building performance method. This means they can model the energy use of their proposed design and show that it meets the overall energy performance targets, even if some individual components differ from the prescriptive path. This flexibility allows for innovative designs and the use of new materials or technologies that might not fit neatly into traditional prescriptive tables. It also encourages a holistic view of building energy performance, where all components work together to achieve efficiency. For more details, see 2024 International Energy Conservation Code details.

Impact on HERS Raters and Energy Professionals

For HERS Raters and other energy code professionals, these updates are critical. As the benchmark for many states and municipalities, understanding the nuances of the 2024 IECC is essential for accurate energy ratings and code compliance verification. Professionals need to be familiar with the new insulation requirements, the various compliance paths, and the advanced provisions laid out in the appendices. Training and continuous education will be important to stay current with these evolving standards. Our analysis shows that this code will require a deeper understanding of building science and energy modeling software to effectively guide builders and ensure compliance.

Which States are Adopting the 2024 IECC?

The 2024 IECC acts as a foundational document for state and city energy codes across the United States. While the IECC itself is a model code, its real impact comes when individual jurisdictions officially adopt it. States and cities often combine the model code with their own specific amendments to tailor it to local climate conditions, economic factors, and policy goals. This process means that while many jurisdictions may adopt the "2024 IECC," the exact requirements can vary slightly from place to place due to these local amendments.

We have seen several jurisdictions already move towards adopting the 2024 IECC. This list includes major cities and entire states, showing a broad recognition of the code's benefits. Among the adopting jurisdictions are Phoenix, Arizona; the state of Colorado; Illinois; the state of Nevada, including Clark County and Las Vegas; New York State and New York City; North Dakota; Rhode Island; Nashville and Davidson County, Tennessee; Austin, Texas; and the state of Utah. This diverse group of adopters highlights the widespread influence of the IECC in shaping energy efficiency standards nationwide.

Specifically, we know that Colorado and Utah have adopted the 2024 IECC with amendments. This means that while they are largely following the framework of the 2024 IECC, they have also added or changed certain provisions to better suit their local needs. For example, a state with very cold winters might add stricter insulation requirements than the base code, or a state with abundant sunshine might enhance the solar-ready provisions. These amendments are a common practice and allow the model code to be more effectively implemented at a local level. It is important for builders and homeowners in these states to consult the specific state or local code to understand all applicable requirements.

Understanding which states and cities adopt the latest IECC is vital for anyone involved in new construction. It determines the minimum energy efficiency standards that must be met for a building to be legally permitted and occupied. For builders operating in multiple states, tracking these adoptions and amendments becomes even more critical to ensure compliance across different projects. The adoption process can take time, involving legislative action, public comment periods, and detailed reviews by state and local agencies. This is why the list of adopting jurisdictions continues to grow as states complete their review processes.

The continuous adoption of updated IECC versions demonstrates a national trend towards more energy-efficient buildings. Each new edition, including the 2024 IECC, aims to improve upon the last, leading to greater energy savings and reduced environmental impact. The fact that jurisdictions are actively reviewing and implementing these codes shows a commitment to these goals. For instance, 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. These statistics provide a strong incentive for states and cities to adopt the newer, more efficient code.

The Adoption Process

The process of adopting a new energy code typically involves several steps. First, the state or local government decides to review the latest IECC model code. Then, they form committees or task forces to analyze the code, propose any necessary amendments, and gather public feedback. This feedback often comes from builders, architects, energy consultants, and consumer groups. After review and public input, the proposed code, including any amendments, goes through a formal legislative or regulatory process for approval. Once adopted, there is usually an effective date, which gives the building industry time to adjust to the new requirements.

Impact of Amendments

Amendments are common because energy needs and priorities can differ significantly across the country. For example, a state like Arizona might focus on cooling loads and solar heat gain, while a state like New York might prioritize heating loads and air sealing in colder climates. These local amendments ensure that the energy code is as effective as possible for the specific climate and regional characteristics. For builders, it means that while the core of the 2024 IECC provides a common framework, they must always verify the specific local code in force for any given project. This is why resources like UpCodes, which tracks jurisdictions adopting the IECC 2024, are invaluable for industry professionals.

Future Adoptions

We expect more states and cities to adopt the 2024 IECC in the coming months and years. The benefits of updated codes—such as lower energy costs, improved comfort, and reduced emissions—provide compelling reasons for jurisdictions to move forward. As the building industry becomes more familiar with the new provisions and the flexibility offered, the transition to the 2024 IECC should become smoother.

How Does the 2024 IECC Impact Builders and HERS Raters?

The 2024 International Energy Conservation Code (IECC) has a direct and significant impact on both homebuilders and HERS Raters, shaping how new homes are designed, constructed, and verified for energy efficiency. For builders, the code aims to prioritize cost-effectiveness and consumer benefits in new construction. This means that while the energy performance targets have become more challenging, the code also provides greater flexibility in how those targets can be met. This allows builders to make choices that are practical, efficient, and tailored to their specific projects and market demands.

One of the key benefits for builders is the wider range of options available to achieve compliance. The 2024 IECC moves beyond a purely prescriptive approach, offering performance-based pathways that allow for more innovative design choices. "Although the 2024 IECC will achieve incrementally higher energy savings than the 2021 edition, the residential provisions will offer substantially more flexibility and a wider range of options for builders to achieve compliance," notes the NAHB (National Association of Home Builders). This flexibility means a builder might choose to invest in a highly efficient HVAC system or advanced fenestration (windows and doors) rather than strictly adhering to a prescriptive insulation R-value, as long as the overall building achieves the required energy performance. This approach maximizes design choices and encourages builders to find the most efficient and practical solutions for their specific projects.

For HERS Raters and other energy code professionals, understanding these updates is absolutely crucial. The 2024 IECC will serve as the benchmark for many jurisdictions, meaning that HERS Raters must be fully proficient in its requirements to accurately assess and verify a home's energy performance. This involves familiarity with the new prescriptive changes, such as the adjusted attic insulation requirements, as well as the various performance modeling options. HERS Raters play a critical role in ensuring that homes are not only designed to meet the code but are also built according to those specifications. Their inspections and testing, including blower door tests for air leakage and duct leakage tests, are essential for verifying compliance and confirming the energy savings predicted by the code.

The code is also designed for practical implementation in the field. This focus on practical application means that the requirements are intended to be achievable with current construction practices and readily available materials, even as they push for higher efficiency. NAHB staff and builder members were involved in the development committees, ensuring that the code's provisions are realistic and can be implemented without undue burden on the construction industry. This involvement helps to bridge the gap between theoretical energy goals and the realities of building homes on the ground. For us, this collaborative approach is vital for the successful adoption and implementation of new energy codes. For more details, see NAHB analysis of 2024 IECC savings.

The 2024 IECC includes various appendices that impact how builders and raters approach specific aspects of construction. For example, Appendix RB outlines solar-ready provisions, requiring builders to consider future solar installations in their designs. Appendix RE addresses electric vehicle charging infrastructure, pushing builders to include necessary wiring. And Appendix RK focuses on electric-ready residential building provisions, preparing homes for a future shift to all-electric systems. For HERS Raters, these appendices mean new items to inspect and verify, ensuring that the infrastructure is in place to support these future energy technologies. The integration of these forward-looking elements into the code ensures that new homes are not only energy-efficient today but are also prepared for the energy demands of tomorrow.

Training and Education for Professionals

The updates in the 2024 IECC necessitate ongoing training and education for builders, HERS Raters, and other energy professionals. Workshops, seminars, and certification programs will be essential to ensure that the industry understands and can effectively implement the new code requirements. For HERS Raters, staying current with the latest energy modeling software and testing protocols aligned with the 2024 IECC is particularly important for accurate assessments. We emphasize the importance of continuous learning to maintain expertise in this evolving field.

Verification and Testing

The role of verification and testing remains central to the 2024 IECC. Requirements for blower door testing to measure air leakage and duct leakage testing ensure that the building envelope and HVAC systems perform as designed. HERS Raters conduct these tests, providing objective data on a home's energy performance. The results of these tests directly impact whether a home passes code compliance. The 2024 IECC continues to rely on these critical measurements to confirm that the energy efficiency goals are actually being achieved in constructed homes.

Cost-Effectiveness and Consumer Benefits

The focus on cost-effectiveness and consumer benefits means that the code aims to deliver tangible value to homeowners. The 6.6% energy cost savings determined by the DOE for the 2024 IECC compared to the 2021 edition directly translates into lower monthly utility bills for residents. This makes new, code-compliant homes more attractive to buyers and contributes to long-term affordability. For builders, demonstrating these savings can be a powerful selling point.

What is the Relationship Between the IECC and ENERGY STAR?

The relationship between the International Energy Conservation Code (IECC) and ENERGY STAR is one of foundational requirements versus advanced, voluntary performance. The IECC sets the baseline for energy efficiency in new construction, establishing the minimum standards that all new buildings must meet to be legally constructed. ENERGY STAR, on the other hand, is a voluntary program that certifies homes and apartments that go beyond these minimum code standards, achieving a higher level of energy efficiency.

The IECC ensures that every new home built adheres to a certain level of energy performance, covering critical elements like insulation, windows, and air sealing. It represents the "floor" of energy efficiency. For example, the U.S. Department of Energy (DOE) determined that the 2024 IECC achieves a 7.8% site energy savings and 6.6% energy cost savings compared to the 2021 IECC, meaning it sets a higher baseline than its predecessor. This code is mandatory in jurisdictions that have adopted it, meaning builders must comply to get their projects approved.

ENERGY STAR certified homes are designed to be significantly more energy-efficient than those built only to minimum code standards. This program, which is an official initiative of the United States government, offers a mark of superior energy performance. Homes that earn the ENERGY STAR label undergo a rigorous verification process, often involving a third-party Home Energy Rater, to ensure they meet strict energy efficiency guidelines. These guidelines typically require performance levels well above the IECC minimums. For instance, an ENERGY STAR certified home might feature better insulation, more efficient windows, tighter construction for reduced air leakage, and high-efficiency heating and cooling systems.

The updates in the 2024 IECC will influence the landscape for homes seeking ENERGY STAR certification. As the IECC baseline becomes more stringent, the ENERGY STAR program often adjusts its requirements to maintain its distinction as a higher standard. This dynamic ensures that ENERGY STAR continues to represent leading-edge energy performance. Builders who aim for ENERGY STAR certification are not just meeting code; they are exceeding it, offering homeowners additional benefits in terms of lower utility bills, enhanced comfort, and a reduced environmental footprint. The ENERGY STAR Residential New Construction Program provides comprehensive guidelines for achieving this higher level of efficiency.

For homeowners, understanding the difference is important. A home built to the 2024 IECC will be more efficient than older homes or those built to less stringent codes. However, an ENERGY STAR certified home offers an even greater assurance of energy savings and quality construction. The ENERGY STAR label on a home indicates that it has been independently verified to meet strict energy efficiency criteria, leading to lower operating costs and a more comfortable living environment. The program also provides resources for partners, including builders and energy raters, to help them achieve certification for single-family homes and apartments.

ENERGY STAR as a Voluntary Standard

ENERGY STAR is a voluntary program. This means builders choose to participate and invest in the extra measures required to achieve certification. The incentive for builders often comes from market demand for energy-efficient homes, the ability to command a higher sales price, and access to specific utility incentives or tax credits, such as the § 45L Builder Tax Credit. For consumers, the ENERGY STAR label simplifies the decision-making process, providing a trusted symbol of energy efficiency.

Verification by Third-Party Raters

Both the IECC and ENERGY STAR programs rely on qualified professionals, like HERS Raters, for verification. For IECC compliance, raters might conduct specific tests, like blower door tests, to ensure minimum air sealing standards are met. For ENERGY STAR, the rater's role is more extensive, involving detailed inspections and performance testing throughout the construction process to confirm that all program requirements are satisfied. This independent verification adds credibility to both the code compliance and the ENERGY STAR certification.

Continuous Improvement

Both the IECC and ENERGY STAR programs are committed to continuous improvement. The IECC is updated every three years to incorporate new technologies and higher efficiency goals. Similarly, the ENERGY STAR program periodically revises its specifications to ensure that certified homes remain at the forefront of energy efficiency. This ongoing evolution means that homes built today are significantly more efficient than those built just a decade ago.

What's Next: The 2027 IECC Development?

The evolution of energy codes is a continuous process, and even as the 2024 IECC is being adopted, work is already underway to develop the next edition of the code: the 2027 IECC. This forward-looking approach ensures that energy efficiency standards keep pace with technological advancements, environmental goals, and the evolving needs of the building industry. The International Code Council (ICC) updates the IECC every three years, maintaining a consistent cycle of review and improvement. For more details, see Ekotrope overview of 2024 IECC residential updates.

NAHB (National Association of Home Builders) staff and builder members continue to participate actively in the committees responsible for shaping future code editions. This ongoing involvement is crucial because it ensures that the perspectives of those who build homes are represented in the code development process. Their input helps to ensure that new code provisions are not only technically sound but also practical for implementation in the field, cost-effective, and beneficial to consumers. This collaborative effort helps to avoid mandates that might be difficult or overly expensive for builders to implement, promoting a balanced approach to energy efficiency. The NAHB emphasizes their commitment to ensuring the new energy code prioritizes cost-effectiveness and consumer benefits, maximizes design choices for builders, and can be practically implemented in the field.

The development process for the 2027 IECC will likely follow a similar path to previous editions, involving extensive research, public input, and committee deliberations. Experts from various fields, including building science, engineering, architecture, and energy policy, contribute to this process. They review new technologies, evaluate the performance of existing code provisions, and consider the latest data on energy consumption and environmental impact. This comprehensive review ensures that the next edition of the code will be robust and relevant.

The ongoing development process ensures the code continues to evolve with new technologies and efficiency goals. As we see advancements in areas like smart home technology, renewable energy systems, and advanced building materials, the IECC must adapt to incorporate these innovations. For example, the 2024 IECC already includes appendices on electric vehicle charging infrastructure (Appendix RE) and electric-ready residential building provisions (Appendix RK), indicating a clear direction towards electrification and grid integration. The 2027 IECC will likely build upon these themes, potentially introducing even more aggressive targets for operational carbon reduction, demand response capabilities, or on-site renewable energy generation.

For us in the energy efficiency sector, monitoring the development of the 2027 IECC is essential. It provides insights into future trends and challenges in building energy performance. Understanding the direction of the code allows HERS Raters, energy consultants, and builders to prepare for upcoming changes, invest in relevant training, and adapt their practices accordingly. This proactive approach helps to ensure a smooth transition when the new code is eventually released and adopted by jurisdictions. The goal is always to create buildings that are more efficient, more comfortable, and more sustainable, contributing to a healthier environment and lower energy costs for everyone.

Call for Committees

The ICC regularly issues a call for committees for the next edition of the code. This is how they gather the diverse expertise needed for code development. Individuals with backgrounds in construction, energy efficiency, engineering, and related fields volunteer their time to serve on these committees. Their work involves reviewing proposals for changes, debating the technical merits, and ultimately voting on the language that will form the next edition of the IECC. This open and transparent process is a hallmark of the ICC's code development.

Anticipated Focus Areas

While specific details for the 2027 IECC are still in development, we can anticipate certain areas of focus. Given the trends in the 2024 IECC, it's likely that the 2027 edition will continue to push for greater energy efficiency in the building envelope, potentially through more stringent insulation or window performance requirements. There will also likely be an increased emphasis on reducing operational carbon emissions, integrating more renewable energy sources, and making buildings more "grid-interactive" through demand response controls and energy storage systems. The 2024 IECC already includes appendices on demand responsive controls (Appendix RJ) and electrical energy storage systems (Appendix RD), setting the stage for more comprehensive requirements in future codes.

Long-Term Vision

The continuous development of the IECC reflects a long-term vision for a built environment that is highly energy-efficient and sustainable. Each code cycle brings us closer to achieving ambitious energy and climate goals. For builders, this means continuously adapting and innovating. For homeowners, it means benefiting from homes that are increasingly comfortable, affordable to operate, and environmentally friendly. The 2027 IECC will be another significant step on this path.

Frequently Asked Questions

What does IECC stand for?

IECC stands for the International Energy Conservation Code. It is a model building code developed by the International Code Council (ICC) that sets minimum energy efficiency standards for new construction. The code covers various aspects of a building's energy performance, including walls, floors, ceilings, lighting, windows, doors, duct leakage, and air leakage. The IECC was first created in 2000 and is updated every three years.

How often is the IECC updated?

The International Energy Conservation Code (IECC) is updated every three years by the International Code Council (ICC). This regular update cycle ensures that the code incorporates the latest advancements in building science, energy-saving technologies, and best practices. For example, the 2024 IECC is the latest edition, following the 2021 IECC, and work is already ongoing for the 2027 IECC.

Is the 2024 IECC mandatory in all states?

No, the 2024 IECC is not mandatory in all states automatically. It is a model code, which means states and local jurisdictions must officially adopt it to make it legally binding. Many states and cities, such as Colorado and Utah, have adopted the 2024 IECC, often with local amendments to suit their specific needs. However, the exact energy code in force can vary widely by jurisdiction.

What are the main benefits of the 2024 IECC for homeowners?

The main benefits of the 2024 IECC for homeowners include lower energy bills and increased comfort. The U.S. Department of Energy (DOE) determined that the 2024 IECC achieves a 6.6% energy cost savings compared to the 2021 IECC, meaning homes built to the new code will be cheaper to heat and cool. Additionally, improved insulation and air sealing requirements lead to a more consistent indoor temperature and fewer drafts, enhancing overall comfort.

How does the 2024 IECC address renewable energy?

The 2024 IECC addresses renewable energy through several provisions, primarily in its appendices. For residential buildings, Appendix RB includes solar-ready provisions for detached one- and two-family dwellings and townhouses, making it easier to install solar panels later. Appendix RC outlines zero net energy residential building provisions, guiding homes towards producing as much energy as they consume. The code also includes an appendix for on-site renewable energy (Appendix RI), further supporting the integration of clean power sources.