ANSI/ASHRAE/IES Standard 90.1-2019

On April 21, 2021, DOE issued a preliminary determination that Standard 90.1-2019 will achieve greater energy efficiency in buildings subject to the code. DOE estimates national savings in commercial buildings of approximately:

  • 4.7 percent site energy savings
  • 4.3 percent source energy savings
  • 4.3 percent energy cost savings
  • 4.2 percent carbon emissions

Additional information related to this action, including the official Federal Register publication and docket containing public comments received, is available at

State Certification

Upon publication of an affirmative determination, States are required to certify that they have reviewed the provisions of their commercial building code regarding energy efficiency, and, as necessary, updated their codes to meet or exceed the updated edition of Standard 90.1. Additionally, DOE provides guidance to States on submitting certification statements and requests for deadline extensions.

Supporting Analysis

DOE conducted a technical analysis in support of its determination. This analysis assesses Standard 90.1 compared to the previous edition and estimates the anticipated energy consumption of buildings required to meet the updated Standard.

For more information, please contact:

Jeremy Williams, Building Energy Codes Program

With each new edition of ANSI/ASHRAE/IES Standard 90.1, DOE is required by statute to issue a determination as to whether the updated edition will improve energy efficiency in commercial buildings. (42 U.S.C. 6833)

Commercial Buildings

(2)(A) Whenever the provisions of ASHRAE Standard 90.1-1989 (or any successor standard) regarding energy efficiency in commercial buildings are revised, the [DOE] Secretary shall, not later than 12 months after the date of such revision, determine whether such revision will improve energy efficiency in commercial buildings. The [DOE] Secretary shall publish a notice of such determination in the Federal Register.

(B)(i) If the [DOE] Secretary makes an affirmative determination under subparagraph (A), each State shall, not later than 2 years after the date of the publication of such determination, certify that it has reviewed and updated the provisions of its commercial building code regarding energy efficiency in accordance with the revised standard for which such determination was made. Such certification shall include a demonstration that the provisions of such State's commercial building code regarding energy efficiency meet or exceed such revised standard.

(ii) If the [DOE] Secretary makes a determination under subparagraph (A) that such revised standard will not improve energy efficiency in commercial buildings, State commercial building code provisions regarding energy efficiency shall meet or exceed ASHRAE Standard 90.1-1989, or if such standard has been revised, the last revised standard for which the [DOE] Secretary has made an affirmative determination under subparagraph (A).

DOE typically performs a combination of qualitative analysis (i.e., comparison of individual code provisions) and quantitative analysis (i.e., whole-building simulation) in support of its determinations. The outcome of this analysis supports a determination as to whether new provisions improve building energy efficiency, as would be regulated by the updated code.

Previous DOE determinations surrounding building energy codes are available for reference by states and local governments, as well as other interested stakeholders.