Residential Determination

2015 International Energy Conservation Code

On June 11, 2015, DOE issued a determination that the 2015 IECC would achieve greater energy efficiency in buildings subject to the code. DOE estimates national savings in residential buildings of approximately:

  • 0.73% energy cost savings
  • 0.87% source energy savings
  • 0.98% site energy savings

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 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 2015 IECC must be submitted by June 12, 2017.

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.