Buildings Summary
Building codes are a foundational policy that ensures energy efficiency is integrated into all new buildings statewide. If energy efficiency is not incorporated at the time of construction, the new building stock represents a “lost opportunity” for energy savings because it is difficult and expensive to install efficient measures and equipment after construction is completed. Mandatory building energy codes are one way to target energy efficiency by requiring a minimum level of energy efficiency for all new residential and commercial buildings in a state. Enforcing compliance with building codes can be difficult and costly, but a concerted effort to fund and train code officials has the potential to generate significant energy savings for a state, helping consumers to save money on their energy bills and thereby making businesses more viable and homes more affordable.
Alabama has mandatory building codes for both residential and commercial buildings, and a May 2024 bill bans more stringent local energy codes. The state's residential code references to the 2015 IECC, however, state-specific amendments weaken it significantly. The state's commercial code references ASHRAE 90.1-2013. Alabama has completed limited code compliance activities.
Building energy codes apply to state-financed residential buildings, but not other new construction. Alaska has made several efforts to ensure code compliance, including establishment of a stakeholder advisory group and completion of a gap analysis.
Arizona is a home-rule state, however, the majority of new construction activity occurs in jurisdictions who have adopted the 2012 IECC or 2015 IECC. Utilities are involved in code compliance support activities, and the state organizes code training and outreach.
Arkansas has mandatory energy codes for both residential and commercial buildings, though municipalities are allowed to adopt codes more stringent than the statewide mandatory code. The 2014 Arkansas Energy Code for New Building Construction, also known as the 2014 Arkansas Energy Code, is based on the 2009 IECC with amendments. The state has completed several code compliance activities, including a gap analysis and training and outreach.
California first adopted Building Energy Efficiency Standards in 1978, and has regularly updated them approximately every three years. California’s energy code is considered to be one of the most aggressive and best enforced energy code in the United States, and has been a powerful vehicle for advancing energy-efficiency standards for building components and equipment. The Standards are required by statute to be performance-based, offering flexibility for builders and designers. The code also stands out because it includes field verification (residential) and acceptance testing (nonresidential) requirements for certain measures that are prone to construction defects or improper commissioning, and because high compliance rates overall are reported for requirements for newly constructed buildings. California's codes help work towards their goal of a 100% clean energy grid and carbon-neutrality by 2045.
Colorado is a home-rule state, but under state statute (House Bill 19-1260), local jurisdictions are required to adopt one of the three most recent versions of the International Energy Conservation Code at a minimum, upon updating any other building code, with more stringent codes as time progresses. As of November 2024, nearly 97% of Colorado's population is on the 2015, 2018, or 2021 IECC.
Additional information on Colorado building energy codes can be found here.
Several local jurisdictions have strengthened their building energy codes by requiring electric vehicle readiness and net zero energy construction, among other green construction requirements.
The Connecticut Department of Administrative Service incorporated the 2021 ICC family of codes as part of the state building code-which was adopted in October 2022. As part of the 2022 state building code, the state will implement the 2021 IECC in residential and commercial buildings. The CT state building inspector is working with the Codes and Standards Committee to draft the 2025 state building code, which incorporates by reference the 2024 International Energy Conservation Code. The estimated date of adoption is Fall 2025.
Residential and commercial codes follow the 2018 IECC and ASHRAE 90.1-2016. Localities may adopt more stringent stretch codes, but none have done so to-date. The state has completed a gap analysis and baseline compliance study.
Delaware Code also requires the state to establish programs to promote the construction of zero net energy homes and commercial buildings by December 31, 2025 and December 31, 2030 respectively. It is within this context that stretch codes may be considered in the future.
Washington, DC requires compliance with the 2015 IECC and ASHRAE 90.1-2013 for residential and commercial buildings, and requires large new construction to comply with the International Green Construction Code (IgCC). The codes also include an alternative compliance pathway for net zero buildings, including LEED Zero Energy and LEED Zero Carbon, for both commercial and residential construction. Code compliance and outreach efforts are led by the District Department of Consumer and Regulatory Affairs' Green Building Division.
Effective December 31, 2023, Florida law requires that residential and commercial buildings comply with the 8th Edition (2020) Florida Building Code, Energy Conservation. This consists of the foundation code 2021 International Energy Conservation Code (IECC) and amendments for low-rise residential buildings, and the 2019 ASHRAE 90.1 standard for all other buildings.
The 2020 Georgia State Minimum Standard Energy Code Georgia 2020, based on the 2015 IECC with state specific amendments, went into effect January 1, 2020. Southface Institute, in partnership with Georgia Environmental Finance Authority (GEFA) and the Department of Community Affairs (DCA), has developed comprehensive trainings and resources to help building professionals comply with the latest codes.
On January 29, 2023, the 2021 IECC-R became the state residential energy code by default and without any amendments from the State Building Code Council per Hawai'i Revised Statutes 107-24(c). This code took effect for all State Government residential buildings on January 29, 2023. The counties have until January 29, 2025, to adopt the 2021 IECC-R with local amendments, or the state code shall become the county code by default.
The State of Idaho adopted the 2018 IRC and IECC residential provisions as well as the 2018 IECC commercial provisions, both with amendments, during the 2020 legislative session. Both codes will take effect on January 1, 2021. This code adoption will replace Idaho’s current building code standards and bring all jurisdictions with building codes up to the 2018 IECC standard. Idaho statute prohibits local jurisdictions from adopting more stringent building codes than what is adopted by the state.
The Illinois Energy Conservation Code supersedes home rule and is the minimum code for all affected buildings in the State of Illinois. Commercial and residential buildings must comply with 2021 IECC standards. The state has implemented several activities to ensure code compliance, including convening a stakeholder advisory group, conducting compliance studies, and offering code trainings.
Residential construction in Indiana must comply with the 2018 IECC with amendments, and commercial buildings must meet ASHRAE 90.1-2007 standards. The state has completed limited activities to ensure code compliance, including training and outreach.
In Iowa, the commercial Energy Code is the 2012 IECC with ASHRAE 90.1 2010 allowed by reference. The residential Energy Code is the IECC 2012 with Iowa specific amendments. Iowa is a hybrid home rule state, meaning there are four statewide codes, the IECC 2012, IMC 2015, IFC 2015 and the NEC 2017. The IECC 2012 is adopted as a statewide code and does not need adoption by the local jurisdictions as it is a state code/law. Jurisdictions are permitted to adopt codes more stringent than the state code. There are jurisdictions that have adopted the IECC 2015. The state has completed many activities to ensure code compliance, including training and outreach and compliance studies. Utilities are involved in code compliance efforts.
Kansas is a home rule state. The Kansas Corporation Commission conducts an annual survey to assess code compliance. The Kansas Corporation Commission’s Energy Division will continue to survey local jurisdictions – cities and counties that, taken together, account for over 90% of the state’s residential construction activity – and publish the findings annually.
Residential construction must comply with the 2009 IECC with state amendments, while commercial construction must comply with the 2012 IECC. The state completed a gap analysis and strategic compliance plan in 2011. The state is also undergoing a code improvement/compliance study in partnership with the U.S. Department of Energy and Pacific Northwest National Labs.
Residential buildings must meet the 2009 IRC with reference to the 2009 IECC, while commercial and state-owned construction must meet ASHRAE 90.1-2007. The state offers code trainings.
In 2019, the Technical Codes and Standards Board formally decided to adopt the 2015 IRC, IEBC, and IECC and commenced a rulemaking process to update the Maine code. The MUBEC Board accepted the 2021 edition of all of the IRC, IEBC, and the IECC, and these rules will become effective in 2024 upon final review and approval by the Attorney General.
In 2020, state law required the Maine Climate Council to develop a new climate action plan. The plan, titled Maine Won't Wait: A Four-Year Plan for Climate Action, was issued in December of 2020, and identified among its top priorities the strategy to "Modernize Maine's Buildings." The strategy includes a recommendation to develop a long-term plan by 2024 to phase in modern, energy-efficient building codes to reach net-zero carbon emissions for new construction in Maine by 2035. In addition, it sets a goal to enhance existing training on building codes and expand these programs to support ongoing education of contractors and code-enforcement officials.
Last reviewed: November 2024
The 2018 Maryland Building Performance Standards (MBPS) are mandatory statewide and reference the 2018 IECC for residential and commercial buildings. Localities are permitted to adopt stretch codes that are more stringent than the statewide code. The state has implemented a variety of measures to ensure code compliance. The 2021 IECC is currently under review for adoption (as of November 2024).
The Board of Building Regulations and Standards adopted the 2018 IECC and ASHRAE Standards 90.1-2016, with strengthening amendments. The state stretch energy code remains as a requirement to exceed the baseline state code by approximately 10% for new large commercial construction, or to require a HERS rating of 55 or less or a Passive house certification for new low-rise residential construction. Adoption of the Massachusetts stretch energy code has continued to grow, it is now adopted in 301 towns and cities. Massachusetts has implemented a variety of activities to ensure robust energy code training and compliance.
The state's Next Generation Roadmap for Climate Policy legislation signed in March 2021 also calls for development of an opt-in net-zero stretch code that defines a net-zero building and net-zero building performance standards.
Last reviewed: July 2021
Michigan is operating under the 2015 Michigan Residential Code and the 2015 Michigan Uniform Energy Code. The state is currently in the process of completing an update of the residential energy code to the most recent IECC 2021 code.
Minnesota currently has the 2012 IECC in effect for residential construction; as of March 2020, the 2018 IECC is in place for commercial construction. The state offers code training and outreach, and has completed a compliance study.
Mississippi is a home rule state, with a voluntary residential code based on ASHRAE 90-1975, Commercial codes were updated in 2013, setting the mandatory energy code standard for commercial and state-owned buildings as ASHRAE 90.1-2010. Jurisdictions can adopt more stringent codes. The state has completed a baseline compliance study, established a stakeholder advisory group, and offers training and outreach.
Missouri is a home-rule state. About 50% of the state's population is covered by the 2009, 2012, 2015, or 2018 IECC or equivalent codes. The state has completed a gap analysis and has established a stakeholder advisory group.
Montana's building energy codes are mandatory statewide. The current residential code requires compliance with the 2018 IECC, with amendments. The commercial code requires compliance with the 2018 IECC or ASHRAE 90.1-2016. Localities are permitted to adopt stretch codes as long as incentives are provided to pursue the higher level of code stringency, however, no localities have pursued stretch codes to date.
Nebraska is a home-rule state. Effective July 1, 2020, the Nebraska Energy Code (NEC) requires residential and commercial buildings to comply with the 2018 IECC. The state has completed a comprehensive set of activities to ensure compliance with building energy codes.
Nevada Revised Statute 701.220 requires the Director of the Governor’s Office of Energy to adopt the most recent version of the IECC. As of July 28, 2021 the 2021 IECC is effective for commercial and residential buildings statewide, however, municipalities then must adopt the code individually. ASHRAE Standard 90.1-2016 is also an acceptable compliance path for commercial buildings in Nevada.
Effective July 2022, the NH legislature adopted the 2018 ICC codes with state-specific energy related amendments to the 2018 IRC. The code is mandatory statewide. The state also conducted a compliance study in 2012, and recently held training sessions on residential and commercial code compliance.
As of September 2022, New Jersey adopted without amendments the 2021 International Energy Conservation Code (IECC) for residential structures, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 90.1-2019 for commercial structures, and the zero energy code provisions in the 2021 IECC-Appendix CC as optional at the discretion of the permit applicant for commercial structures. It also recently completed a sweeping code compliance study.
In August 2020, the New Mexico Construction Industries Commission (CIC) voted to adopt the 2018 New Mexico Energy Conservation Code (NMECC), based on the 2018 IECC with state-specific amendments. The new code reduces energy use in new residential and commercial buildings by about 25 percent relative to the previously adopted 2009 IECC.
Residential buildings must comply with the 2018 IECC and commercial buildings must comply with the 2018 IECC or ASHRAE 90.1-2016, although local governments may adopt more stringent building energy codes. NYStretch Energy Code-2020 was published July 2019 for voluntary, local adoption. To date, NYStretch has been adopted by 14 local governments, including New York City.
Last reviewed: November 2024
Residential and commercial buildings must comply with the 2018 North Carolina Energy Conservation Code (NCECC), based on the 2015 IECC with amendments. The state offers code training and outreach.
North Dakota is a home rule state and has no statewide mandatory energy codes. The voluntary energy code is under the purview of the North Dakota State Building Code and the state Building Code Advisory Committee has the authority to make recommendations that could include energy standards future editions of the State Building Code. North Dakota recently adopted the 2021 IECC as its voluntary statewide code – without commercial amendments and with weakening residential amendments – and 91% of the state population resides in jurisdictions that have adopted this code update.
Effective July 1, 2019, a new residential code will be in effect based upon the 2018 IRC/IECC with amendments. Ohio's commercial energy code is mandatory statewide and references both the 2012 IECC and 2010 ASHRAE 90.1 with amendments. The state has completed a gap analysis, offers training and outreach, and involves utilities in code compliance activities. There is no statutory review or update requirement specific to energy codes. However, there is a general statutory requirement for state agencies to review rules every 5 years.
Residential buildings must comply with the 2015 IRC; however, the energy chapter references the 2009 IRC. Similarly, commercial buildings must comply with the 2915 ICC/IBC standards, but the energy chapter references the 2006 IECC. Oklahoma does not currently require all jurisdictions to adopt a statewide energy code. The state allows its local jurisdictions to adopt building codes other than the state standards, but none have adopted any standards more stringent than the statewide base code. The state has completed a gap analysis and offers training and outreach. State Minimum Building Energy Codes are amended by the Oklahoma Uniform Building Code Commission (OUBCC) and adopted by the Legislature.
The state's residential building code is equivalent to the 2018 IECC, while the commercial building code utilizes ASHRAE 90.1-2019. The state has completed a variety of activities to ensure compliance, including establishing a stakeholder advisory board. Utilities are involved in code compliance efforts.
Residential buildings must comply with the 2015 IECC, while commercial buildings must comply with the 2015 IECC, with reference to ASHRAE 90.1-2013. The state has completed a gap analysis and offers code training and outreach.
Residential and commercial buildings are required to comply with the 2018 IECC and ASHRAE 90.1-2010 with state-specific weakening amendments. Rhode Island now has a voluntary stretch code for commercial and residential buildings. The 2024 IECC is anticipated to be adopted for both residential and commercial buildings. Rhode Island has completed a comprehensive set of activities to ensure code compliance.
Residential and commercial building energy codes reference the 2009 IECC. South Carolina has completed a gap analysis and conducts training and outreach to encourage code compliance.
There is no mandatory statewide energy code, but the 2009 IECC is a voluntary residential standard. Local jurisdictions may opt out of the state's commercial code. South Dakota completed a gap analysis in 2011.
Since Tennessee is a home rule state, codes are adopted and enforced at the jurisdictional level. In August 2019, the state adopted the 2018 IRC and the 2018 IECC codes with amendments for residential construction. This change went into effect on July 16, 2020. Commercial and state-owned buildings must comply with the 2012 IECC. Tennessee has hosted code training sessions.
Single-family residential construction must comply with the 2015 IRC. All other residential and commercial building construction must comply with the 2015 IECC. State-funded building construction must comply with ASHRAE 90.1-2013 starting June 1, 2016. The state works with a stakeholder advisory group, has completed a baseline study, and offers training and outreach.
During the 2019 legislative session, the Utah legislature passed HB 218, which will adopt the 2018 IECC for commercial provisions in its entirety. The amended 2015 IECC residential provisions remain as the statewide residential energy code, with several incremental stringency improvements starting in 2019.
The Vermont Residential Building Energy Standards (RBES) are mandatory statewide. The current RBES became effective July 1, 2024 and is based on the 2015 Vermont RBES language and also includes all the IECC 2018 and 2021 energy efficiency requirements, and many of the IECC 2024, as well as select language updates and additional, more stringent Vermont energy efficiency requirements.
With an effective date of January 18, 2024, Virginia's Uniform State Building Code (USBC) has been updated to incorporate energy efficiency provisions for commercial buildings of the 2021 IECC and ASHRAE 90.1-2019. All buildings with permit application date of January 18, 2025 or after must comply. Residential buildings must meet requirements of the residential provisions of the 2021 IECC, with two mild weakening amendments: (1) wall insulation R-Value maintained at R-15 or R-13+1; (2) building thermal envelope air leakage rate not exceeding five air changes per hour. The code development process for the 2024 USBC (which includes the 2024 Virginia Energy Conservation Code), is anticipated to begin Q3 of 2024. The 2024 USBC will be using the 2024 I-Codes as the model codes.
The 2018 Washington State Energy Code is a state-developed code that is mandatory statewide. While based on the 2018 IECC, residential provisions have been extensively modified to provide savings greater than the model code. Commercial provisions have been extensively modified to reach state specific energy reduction targets incorporating parts of ASHRAE 90.1, ASHRAE 90.4 as well as unique features. The resulting code provides savings equivalent to the ASHRAE 90.1 -2016. The state code specifically implements a standard that directly addresses carbon emissions reductions by adopting a unique version of ASHRAE 90.1 Appendix G.
Washington has completed a variety of activities to ensure compliance and involves utilities in its efforts.
Last reviewed: August 2020
Residential buildings must comply with the 2009 IECC, while commercial buildings must meet ASHRAE 90.1-2010 standards due to a code update in 2019. These codes are mandatory, but adoption by jurisdictions is voluntary. West Virginia has convened a stakeholder advisory group and offers code training and outreach.
The state-developed residential code is based on the 2009 IECC. In May 2018, the state updated its commercial building energy codes to reference the 2015 IECC/ASHRAE 90.1-2013, albeit substantial weakening amendments. Wisconsin has completed a baseline compliance study and offers code training.
The state's ICBO Uniform Building Code is voluntary for both residential and commercial buildings and is based on the 1989 MEC. Wyoming has convened a stakeholder advisory group and offers code training and outreach.