DOE is required by statute to issue a determination as to whether updated editions of the International Energy Conservation Code (IECC) would improve energy efficiency in residential buildings subject to the code. If this determination is finalized, States will be required by statute to certify that they have reviewed the provisions of their residential building code with regard to energy efficiency and made a determination as to whether to update their code to meet or exceed the 2015 IECC. Additionally, this notice provides guidance to States on certifications and requests for extensions of deadlines for certification statements.