These analyses evaluate the cost-effectiveness of the prescriptive path of the 2015 edition of the International Energy Conservation Code (IECC), relative to the 2012 and 2009 IECC for all 50 states and the District of Columbia. The analysis covers one- and two-family dwelling units, town-homes, and low-rise multifamily residential buildings covered by the residential provisions of the 2015 IECC.

A research project in the state of Maryland investigated energy code-related aspects of residential single-family new construction. The study was initiated in January 2015 and continued through July 2015. During this period, research teams visited 207 homes during various stages of construction, resulting in a substantial data set based on observations made directly in the field.

PNNL evaluated the cost effectiveness of the changes in the prescriptive and mandatory residential provisions of the 2021 edition of the IECC, compared to those in the prior edition, the 2018 IECC.