Building Efficiency

  • Introduction
  • Building EE Codes
  • Stretch Codes
  • Performance-Based Standards
  • Consumption Disclosures and Benchmarking


States have deployed a broad range of policies to reduce building energy consumption and greenhouse gas emissions. The most common policy implemented by states in the area of building efficiency relates to the state’s building code. The vast majority of states implement a state-level energy efficiency (EE) code, with a smaller number of “home rule” states leaving building code enforcement and adoption entirely up to local governments. 

In addition to implementing a mandatory building energy code, some states have voluntary energy conservation requirements known as “stretch codes” that are more aggressive than the mandatory requirements. Other states have performance-based targets that establish greenhouse gas emissions reduction or energy conservation requirements for buildings, with at least one state implementing a binding advanced net-zero requirement. 

States have also taken action to increase information-sharing about building energy usage by imposing benchmarking requirements—mandating that building owners track and report energy consumption—and implementing energy efficiency disclosure requirements. Additionally, while a number of states, such as Minnesota, implement “lead by example” policies requiring state government buildings to engage in energy benchmarking and achieve energy performance targets, such state policies are not included in our analysis. 

Recent Action on Building EE Codes 

The most commonly adopted codes and standards are the International Energy Conservation Code (IECC) and the ASHRAE 90.1 standards. The IECC establishes minimum efficiency requirements for heating and ventilation, water, lighting and power usage in new commercial and residential building systems. The ASHRAE 90.1 standards relate to building envelope, air conditioning, heating, power and ventilation in commercial buildings. The IECC standards are designed to incorporate many of the ASHRAE requirements. 

A number of states have recently acted to update their existing EE codes. These states adopted a more recent version of the above standards, with a handful of states enacting the most current IECC and ASHRAE 90.1 requirements. According to the American Council for an Energy-Efficient Economy’s (ACEEE) 2019 energy efficiency scorecard, recent Department of Energy analyses shows that the 2016 version of ASHRAE 90.1 standards—which update lighting and mechanical requirements and building envelope standards—saves 6.7% more energy compared to the 2013 version of the standards. The 2018 IECC, which makes minor changes to window and onsite renewable energy requirements, increases energy savings by 1.7% compared to the 2015 version. 

At least 12 states, including California, Illinois, Maryland, Massachusetts, Nebraska, Nevada, New Jersey, Ohio, Oregon, Utah, Vermont and Washington have adopted the 2018 IECC or equivalent standards for residential or commercial buildings. Note that our analysis highlights only those states that have taken recent action to update their existing codes to adopt a more recent version of the standards. For a current comprehensive list of state EE codes, please see the resources provided by the U.S. Department of Energy and ACEEE.


This interactive map let you read a summary of the state actions.

Display all states


Alabama updated its building energy codes by regulation in 2017 to require that commercial buildings meet the 2015 IECC or 2013 ASHRAE-90.1 standards. For residential buildings, Alabama adopted the 2015 IECC with state-specific amendments. Ala. Admin. Code, 305-2-4.


While California implements state-specific standards highlighted in the “Performance-Based Standards” section, the U.S. DOE has determined that California’s residential and commercial building standards satisfy the 2018 IECC and 2016 ASHRAE 90.1 standards respectively.


Although Colorado is a home-rule state, state law requires local jurisdictions that adopt building energy efficiency codes to meet minimum requirements. In 2019, Colorado enacted HB 1260, requiring local governments with building energy codes to adopt at a minimum one of the three most recent versions of the IECC. The law further encourages local governments to notify the state energy office upon updating or making any changes to their energy codes. See also Colo. Rev. Stat. § 30-28-201. 


Florida’s 2017 building energy conservation code is based on the 2015 IECC with state-specific amendments. The commercial building requirements reference the 2013 ASHRAE 90.1 standards. 2017 Florida Building Code, Energy Conservation (Sixth Edition).


Georgia recently updated its state minimum energy efficiency code to require compliance with the 2015 IECC or 2013 ASHRAE 90.1 standards with state-specific amendments. This was the first revision the state made to its energy code in over a decade. See Georgia International Energy Conservation Code Supplements and Amendments 2020.


In 2017, Hawaii adopted the 2015 IECC with state amendments for commercial and residential buildings. Hawaii Admin. Rules § 3-181.1.


Under state law, local governments are permitted to adopt a version of the IECC that has been adopted by the state building board with some flexibility in revising the board-approved code to “reflect local concerns,” provided such revisions do not diminish the protectiveness of the standards. Idaho Stat. Ann. § 39-4116. The state currently implements the 2015 IECC for commercial buildings and the 2012 IECC for residential buildings. Idaho Admin. Code


State law requires the adoption of the latest version of the IECC for residential and commercial buildings as the minimum energy code in the state. Ill. Comp. Stat. Ann. 20 § 3125/15; 20 § 3125/10. Illinois currently implements the 2018 IECC for residential and commercial buildings. 71 Ill. Admin Code, pt. 600. Note that the state’s commercial code also references the 2016 ASHRAE 90.1 standards.


In 2019, Maine enacted House Paper 1001, requiring that the state uniform building and energy code contain two of the most recent versions of building codes and guidelines including the IECC and ASHRAE 90.1 standards.


State law requires state regulators to adopt the most recent IECC, among other building standards, within 18 months after the latest version of the code is issued. Md. Public Safety Code, § 12-503. In addition, local governments must implement and enforce a modified state code no later than 12 months after modifications are adopted. Md. Public Safety Code, § 12-505. The state currently implements to the 2018 IECC for all newly constructed and renovated commercial and residential buildings. Illinois previously implemented the 2015 IECC.


State law requires adoption of the latest version of the IECC, along with any strengthening provisions the board of building regulations and standards deems warranted. Mass. Gen. Laws Ann. 143 § 94. Massachusetts currently implements the 2018 IECC for commercial and residential buildings with strengthening amendments and references to the 2016 ASHRAE 90.1 standards. See Ninth Edition Code Mass Regs. 780.


The state currently implements the 2015 IECC for residential buildings. Mich. Admin Code 408.31059 et seq. Michigan also requires that new commercial buildings adhere to the 2015 IECC and 2013 ASHRAE 90.1 standards. Mich. Admin Code 408.31087 et seq.


Similar to Colorado, Nebraska is a home-rule state, but requires local governments to adopt a mandatory statewide energy code. In those jurisdictions without a local code, the state will step in and enforce the minimum building efficiency requirements. In 2019, Nebraska updated its state energy code to require minimum compliance with the 2018 IECC. The state had previously required compliance with the 2012 version of the standards. Additionally, the new law requires local governments to notify the state energy office within 30 days upon modifying local codes to delete certain portions of the 2018 IECC. Legislative Bill 405 (2019).


State law requires local government adoption of the most recent version of the IECC standards as the minimum building efficiency requirements. Nev. Rev. Stat. 701.220. The 2018 IECC applies to new residential and commercial buildings.

New Hampshire

In 2019, New Hampshire enacted a law updating its state building code to require compliance with the 2015 IECC. The state had previously required compliance with the 2009 version of the standards. HB 562 (2019).

New Jersey

New Jersey requires compliance with the 2018 IECC for residential buildings and the 2016 ASHRAE 90.1 standards for commercial buildings.  N.J. Admin Code 5:23-3:18.

New York

The state updated its EE codes in 2016 to require compliance with the 2015 IECC and 2013 ASHRAE 90.1 standards in addition to a state supplement. N.Y. Codes, Rules and Regs., 19 § 1240. Local governments may adopt the state code or adopt and enforce their own code pursuant to N.Y. Energy Law § 11-109.

North Carolina

In 2018, North Carolina updated its state energy code to require that new residential and commercial buildings comply with the 2015 IECC. See 2018 North Caroline Energy Conservation Code.  


The state’s building energy code is implemented and enforced by regulation and requires compliance with either the IECC or ASHRAE 90.1 standards. Ohio Admin. Code 4101:1-13. The state currently implements standards based on the 2018 IECC with amendments for residential buildings. See Ohio Admin. Code 4101:8-1. For commercial buildings, the state’s standards incorporate both the 2012 IECC with amendments and the 2010 ASHRAE 90.1 standards. Ohio Admin. Code 4101:1-13.


Oregon’s Zero Energy Ready Commercial Code, adopted in 2019, is based on the 2016 ASHRAE 90.1 standards and became fully effective Jan. 1, 2020. The code also requires certain commercial buildings to comply with the 2018 IECC. The state’s current residential building requirements require compliance with the 2015 IECC with state amendments. Note that Oregon is currently developing a Zero Ready Residential Commercial Code to complement its zero energy ready code for commercial buildings.


In 2018, the state adopted the 2015 IECC standards for commercial and residential buildings with state-specific amendments. The state code also adopts certain portions of the 2018 IECC. Penn. Code tit. 34 § 403.21.


In 2015, the state enacted a law adopting the International Residential Code’s 2015 energy efficiency standards for single-family residential buildings and empowering the state energy conservation office to adopt the most recent version of the standards six years later. The law further empowered the state energy conservation office to adopt the latest edition for other residential, commercial and industrial buildings. Tex. Health & Safety Code § 388.003.


In 2019, Utah enacted HB 218, updating its building code to require compliance with the 2018 version of the IECC for commercial buildings only. The state had previously required compliance with the 2015 version of the IECC for both residential and commercial buildings. Utah continues to require compliance with the 2015 IECC for residential buildings.


In December 2019, the state updated its energy code to require that new residential buildings comply with the 2015 IECC and some 2018 IECC amendments. See 2019 Vermont Residential Building Energy Standards (RBES). The state also adopted updates to its energy codes for commercial buildings to require compliance with the 2018 IECC and the 2016 ASHRAE 90.1 standards. See 2020 Vermont Commercial Building Energy Standards (CBES).


The state recently implemented its 2015 Uniform Statewide Building Code requiring new residential and commercial buildings to comply with the 2015 IECC. Virginia is currently in the process of adopting 2018 updates to its statewide code. Virginia 2015 Construction Code, pt. 1 of the Uniform Statewide Building Code.



The state adopted the 2018 IECC for residential and commercial buildings. See Wash. Admin Code  51-11R; Wash. Admin. Code 51-11C.


The state requires compliance with the 2015 IECC or 2013 ASHRAE-90.1 standards for new commercial buildings. Wis. Admin Code SPS 363. New residential buildings are required to comply with the 2009 IECC with state-specific amendments. Wis. Admin Code SPS 322.

Stretch Codes  

While some state legislatures broadly authorize municipalities to adopt building codes that are more stringent than state requirements, others have gone a step further by directing regulators to develop a stretch or optional energy efficiency code for local government adoption. Some states like Arizona, Kansas and Missouri have no statewide building code and leave building code adoption and enforcement exclusively up to local governments. These states and a number of others have “home rule” provisions that grant expanded or exclusive local government power over certain issues and limit state authority in those areas. Some home rule states have minimum building standard requirements, but empower localities to adopt building codes that differ from state requirements. Among those states that empower local governments to adopt differing building codes, some require that local codes be no less stringent than the state code. Others allow local governments to have their own code regardless of stringency, or even no code at all.

At least seven states have enacted stretch or model building codes to support local governments enacting building energy efficiency standards that achieve greater energy savings than the state requirements.

states with stretch code


The state adopted a Green Building Code, mandating compliance with certain green building requirements while providing for compliance with voluntary Tier 1 and Tier 2 standards.


In addition to the mandatory requirements described above, Georgia also provides for local government adoption of permissive energy efficiency codes for certain buildings. Such codes include the 2008 edition of the National Green Building Standards with state-specific amendments as they apply to single and two-family houses and townhouses meeting certain structural requirements.  


In 2019, Maine enacted Senate Paper 480, directing the Technical Building Codes and Standards Board to develop an appendix to the state code with voluntary standards that exceed the state’s Uniform Building and Energy Code. The board is required to develop these standards no later than July 1, 2020.


The state’s stretch codes for residential and commercial buildings are designed to improve energy efficiency in new buildings and may be adopted by any municipality. Mass. Regs. Code tit. 780, § 115 (Appendix AA Stretch Codes).

New York

The New York State Energy Research and Development Authority (NYSERDA) developed the state’s stretch energy codes, which are one cycle ahead of the state’s energy code and designed to reduce greenhouse gas emissions associated with buildings. Information about the state’s stretch codes can be found here.

Rhode Island

In 2018, the state adopted voluntary stretch codes for residential and commercial buildings. These standards were developed in part to aid the state in meeting its green building standards for public facilities (R.I. Gen. Laws § 37-24-4). Information about Rhode Island’s stretch codes can be found here.


In 2013, the state enacted legislation authorizing the commissioner of Public Service to adopt a stretch energy efficiency code for residential buildings. 30 Vt. Stat. Ann. § 51. In addition to developing stretch codes for residential buildings, Vermont also has a stretch code for commercial buildings.

Net-Zero and Performance-Based Standards

Some states have opted for performance-based building efficiency standards in lieu of or as complementary policies to their building energy codes. These policies focus on reducing building energy consumption and greenhouse gas emissions by a certain percentage rather than on specific design features. Some states have even adopted net-zero standards, requiring buildings to generate as much energy as they consume. 

Net-Zero map


State law directs the energy commission to establish a program aimed at achieving energy savings in the state’s existing residential and nonresidential buildings that may include a broad range of programs, including benchmarking and energy ratings, among others. Cal. Pub. Res. Code § 25943. The state developed a comprehensive Energy Efficiency Strategic Plan in 2008 that established ambitious net-zero energy goals for buildings. The plan requires new residential and commercial buildings to be zero-net energy by 2020 and 2030, respectively, and that 50% of existing commercial buildings be retrofitted to achieve zero-net energy by 2030. State regulators subsequently promulgated California’s performance-based building standards with these goals in mind. Under the state’s 2019 Building Efficiency Standards efficiency measures and photovoltaic requirements, single-family homes must use 53% less energy compared to homes built under the 2016 standards. California projects that the energy savings achieved under the residential provisions of the standards will reduce greenhouse gas emissions by 700,000 metric tons over a three-year period. Nonresidential buildings will also use less energy—roughly 30% compared to the 2016 standards—mostly driven by changes to lighting requirements. See Cal. Code of Regs. tit. 24, part 6. In adopting the 2019 building standards, California also adopted certain residential and nonresidential mandatory measures as part of the state’s Green Building Standards Code focusing on design and construction. See Cal. Code of Regs., tit. 24, part 11. The code also includes voluntary standards referenced in the “Stretch Code” section above.


Under state law, all newly constructed residential and commercial buildings must be “zero net energy capable” by 2026 and 2031, respectively. Del. Code Ann. § 7602(c).

District of Columbia

The District’s Clean Energy Omnibus Act of 2018 in part directed regulators to develop building performance standards that align with the district’s short- and long-term climate goals of reducing greenhouse gas emissions, including “carbon neutrality by 2050.” Under the program, all privately-owned buildings with 50,000 square feet or more and all district-owned buildings with 10,000 square feet or more must comply with the standards by 2021. The standards phase-in for smaller privately owned buildings with 25,000 square feet in 2023 and 10,000 square feet in 2026. Additionally, D.C.’s Green Buildings Act requires new or renovated commercial buildings of a certain size to be Leadership in Energy and Environmental Design (LEED) certified. The District discloses the data by making it publicly available on an annual basis. 


State law requires residential and nonresidential buildings to achieve a 70% reduction in annual net energy consumption below 2006 energy code consumption levels. The 70% annual reduction target is phased in starting in 2013 to achieve incremental energy savings until reaching the 70% reduction target by 2031. Rev. Code Wash. 19.27A.160. Additionally, in 2019, the state enacted a new law directing the state Energy Office to adopt and implement energy performance standards for commercial buildings. Buildings that are greater than 50,000 square feet will be required to achieve the standards, which are phased in starting in 2021 as voluntary targets and become mandatory in 2026. See HB 1257.

Energy Consumption Disclosures and Benchmarking

States can encourage building owners to improve the efficiency of their buildings by making energy performance visible to the purchasers, tenants and the public through the use of benchmarking and disclosure policies. Energy is usually a significant expenditure for commercial buildings and homes and most building owners don’t have visibility of where and how a facility’s energy is consumed. The enhanced awareness created by benchmarking helps owners and operators identify opportunities for improving efficiency and reducing costs. Disclosure requirements prior to sale or lease help purchasers and lessors make more informed decisions about the total cost of owning a home, operating a building or leasing property. 

At least 10 states and Washington, D.C., require building owners by statute to benchmark, report energy consumption data or disclose such information prior to sale. While some states implement benchmarking or disclosure policies through regulation or executive order, we’re highlighting states that have enacted legislation on the topic. 

energy consumption map


State law requires utilities to deliver energy benchmarking data to nonresidential buildings as well as nonresidential and residential buildings with five or more utility accounts. Additionally, the state energy commission is tasked with establishing energy benchmarking regulations and requirements related to public disclosure of energy consumption data. Cal. Pub. Res. § 25402.10.

State law also directs the energy commission to establish a statewide home energy rating program that includes labeling procedures. Cal. Pub. Res. Code § 25943.

District of Columbia

District law requires the Department of Energy and Environment to develop data verification and reporting requirements in implementing the performance-based building energy efficiency standards described in the performance-based standards section. D.C. Code § 8-1772.21. District law also requires annual energy benchmarking for existing commercial buildings. D.C. Code § 6-1451.03. To facilitate energy benchmarking requirements, utilities are also statutorily required to take steps to ensure that aggregated monthly energy consumption data is readily accessible to building owners. D.C. Code § 8-1774.07. The District discloses or makes publicly available the benchmarking data on an annual basis. 


The state implements an energy rating system program for all public, commercial and residential buildings. Prospective buyers are entitled to receive information regarding the option for an energy efficiency rating prior to executing the contract for sale. The energy rating system is designed to provide a reliable evaluation of energy consumption and comparison to similar buildings. Fla. Stat. Ann. § 553.990 et seq.


State law requires property owners to share information about building electricity consumption costs prior to sale or lease. Hawaii Rev. Stat. § 508D-10.5.


State law requires the seller of certain new residential buildings to disclose to a prospective buyer information regarding the building’s energy efficiency prior to the execution of the contract for sale. Kan. Stat. Ann. § 66-1228.


Under state law, prospective tenants responsible for paying utility bills have a right to information related to the costs of energy consumption for the previous 12-month period. Upon the request of the lessee, a lessor must provide an energy efficiency disclosure statement. Me. Rev. Stat. Ann. 14 § 6030-C. Additionally, in 2007, the state enacted legislation directing the technical buildings codes and standards board to adopt rules relating to energy performance rating to generate consumer information labels for marketing and sale of residential and commercial buildings. Me. Rev. Stat. Ann. 10 § 9722.

New Jersey

State law requires owners and operators of commercial buildings over 25,000 square feet to benchmark energy and water usage no later than 2023. N.J. Stat. Ann. 48:3-87.10.

South Dakota

Requires sellers of single family or multifamily residential buildings to disclose information regarding building energy efficiency prior to executing the contract for sale. S.D. Cod. Laws  § 11-10-8.


The state recently enacted legislation requiring the state office of energy development to establish rules for a home energy performance rating system to facilitate a voluntary home energy information pilot program designed to increase consumer awareness about home energy efficiency. HB 235 (2020).


State law requires utilities to provide monthly aggregated energy usage data to multiunit building owners upon their request for the purposes of energy benchmarking or creating an energy labeling program. 30 V.S.A. § 63.


The state recently enacted legislation adding energy efficiency data to the required disclosures provided to a buyer of a residential property. SB 628 (2020); HB 518 (2020).


State law requires that nonresidential building owners disclose to prospective lessees, buyers or lenders energy benchmarking data from the previous 12-month period. Wash. Rev. Code 19.27A.170. Additionally, under the state’s recently enacted energy performance standards for commercial buildings, building owners are required to demonstrate compliance with energy use intensity targets.  Wash. Rev. Code 19.27A.210.

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