ARCove collaborated with a statewide team of specialists to analyze the first costs, initial payback, and long term Return on Investment, for residential buildings designed to the 2018 IECC Energy Code versus the 2024 IECC Energy Code. One of ARCove’s single family house designs in Portsmouth was modelled for this study which demonstrates minimal first cost, with modest payback within 2 years, and thereafter substantial gains over the full financing term.