2025 Massachusetts Building Energy Codes

There are three levels of building energy codes in Massachusetts:

• The Base Code is IECC 2021 with MA amendments: 780 CMR Chapter 11R (residential) and 780 CMR Chapter 13 (commercial). The 780 CMR 10th Edition is the current building code for Massachusetts.
• The opt-in Stretch Code is IECC 2021 with key MA amendments: 225 CMR Chapter 22 (residential) and 225 CMR Chapter 23 (commercial).
• The opt-in Specialized Code is IECC 2021 key MA amendments: 225 CMR Chapter 22 + Appendix RC (residential) and 225 CMR Chapter 23 + Appendix CC (commercial).

This map shows which level of code is followed by each municipality.

Links to Code Documents

The latest version of the Stretch and Specialized Codes as of February 14, 2025

IECC 2021

Stretch & Specialized Code - Residential

Stretch & Specialized Code - Commercial

780 CMR 10th Edition (MA Building Code)

2025 Stretch Code Updates Webinar

February 25, 2025 Webinar

Responses to Questions

Webinar Slides

Technical Documents

Stretch Code Technical Guidance

Attachment A: Envelope Performance and Thermal Bridge Derating

Attachment B: ASHRAE Appendix G Relative Performance Simulation Guidelines

Attachment C: Targeted Performance Simulation Guidelines

Schedule and Loads Supplement

Weather File

Stretch Energy Code Study Support

Models Conforming to TEDI Requirements

2024 Public Comments & Stretch Code Updates

The following redlines were made based on public comments and feedback over the last 8+ months. These updates are pending review by the Joint Committee on Telecommunications, Utilities and Energy. DOER expects the final regulations to go into effect in February of 2025.

As part of these edits, DOER made both substantive edits to code and incorporated a significant amount of additional context from the 2021 IECC published by the International Code Council (ICC) to improve the readability of the code. To assist the public's review of these changes, DOER has provided two versions of the redline below.

The "full" version represents both the substantive edits and the 2021 IECC additions in redline. The "abbreviated" version displays only the substantive edits in redline. Please contact [e-mail] with any questions regarding these updates.

September 2024 Public Comments

Fall 2024 Stretch + Specialized Code Commercial Redlines (abbreviated)

Fall 2024 Stretch + Specialized Code Residential Redlines (abbreviated)

Date published:	November 27, 2024