Now is the Time for Communities to Update to the Massachusetts Stretch Code: A Deep Dive into the 10th Edition Base Code and the Stretch Code

This brief is a deep dive into the Massachusetts Stretch Code and 10th Edition Base Code, which is based on the 2021 International Energy Conservation Code. The Base Code applies to new construction and major additions and alterations. A concurrency period, during which time parties may opt to use either the 9th or 10th editions of the Base Code, will occur from September 24, 2024 through June 30, 2025, after which time only the 10th edition Base Code will be in use. The Stretch Code provides additional measures to increase building energy efficiency. Massachusetts also has a Specialized Code that brings new construction in alignment with Massachusetts greenhouse gas limit goals. This document compares the commercial and residential energy efficiency chapters of the 10th edition Base Code to the 9th edition Base Code and the 2025 Stretch Code update to evaluate changes for Massachusetts communities using the Base Code.