A U.S. Department of Energy (DOE) determination is a statute mandated by the Energy Conservation and Production Act for the DOE to review the most recently published energy efficiency codes. Once reviewed, the agency makes their determination on whether the newly published code is more energy-efficient than its predecessor. Below are DOE determinations for the 2015, 2012, and 2009 IECC codes.
DOE also released a determination on Feb 21, 2018 that ANSI/ASHRAE/IES Standard 90.1-2016 will improve the energy efficiency in commercial buildings. Read more here.