Residential Determination

2018 International Energy Conservation Code

On May 2, 2019, DOE issued a preliminary determination that the 2018 International Energy Conservation Code (IECC) will improve energy efficiency in residential buildings. In support of this determination, DOE conducted technical analysis evaluating the impacts of the updated code (relative to the previous 2015 edition). DOE estimates national savings of approximately:

  • 1.97 percent energy cost savings
  • 1.91 percent source energy savings
  • 1.68 percent site energy savings

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

State Certification

Upon publication of an affirmative determination, States are required to certify that they have reviewed the provisions of their residential building code regarding energy efficiency, and made a determination as to whether it is appropriate for them to revise their code to meet or exceed the updated edition of the IECC. Additionally, DOE provides guidance to States on submitting certification statements and requests for deadline extensions. State certifications for the 2018 IECC must be submitted within two years from the date a final determination is published in the Federal Register.

Supporting Analysis

DOE published a technical analysis in support of its determination. This analysis assesses the updated IECC compared to the previous edition, and estimates the anticipated energy consumption of buildings that would be required to meet the code.


With each new edition of the IECC, DOE is required by statute to issue a determination as to whether the updated edition will improve energy efficiency in residential buildings. (42 U.S.C. 6833)

Residential Buildings

(5)(A) Whenever the CABO Model Energy Code*, 1992, (or any successor of such code) is revised, the [DOE] Secretary shall, not later than 12 months after such revision, determine whether such revision would improve energy efficiency in residential buildings. The [DOE] Secretary shall publish notice of such determination in the Federal Register.

(B) 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 the provisions of its residential building code regarding energy efficiency and made a determination as to whether it is appropriate for such State to revise such residential building code provisions to meet or exceed the revised code for which the [DOE] Secretary made such determination.

*As a predecessor to the ICC, the Council of American Building Officials (CABO) was responsible for development of the Model Energy Code (MEC). Contemporary energy codes are referred to and published as the International Energy Conservation Code (IECC)®.

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.