Climate advocates have increasingly pushed for state and local governments to advance more energy efficient building practices. In many communities throughout the Northeast buildings represent a significant portion of a community’s greenhouse emissions impact. Recognizing the need for cost-effective strategies, building energy code officials have become increasingly interested in how to effectively design high-performance building energy codes that can help states and local governments achieve their climate goals. This session will present an in-depth review of the analysis that informed Massachusetts’s new stretch energy code and municipal opt-in stretch code. This session will focus on the key concepts that were evaluated during the analysis including thermal energy demand intensity for a selection of commercial building prototypes. This session will also present an opportunity for discussion between the design community and the DOER staff and consultants involved in the study. (Name of the Muni-opt in code still being finalized.)