Massachusetts residential energy code

Massachusetts residential energy code (2021 IECC with Massachusetts amendments (780 CMR chapter 11R, 10th edition))

As of 2026-10-22. DOE's Building Energy Codes Program (energycodes.gov) lags state adoption, so where a state's own rule was read it governs and DOE's differing figure is noted. Residential means one- and two-family dwellings and townhouses. Local amendments can apply; check the code body before relying on a section.

Key features

Code in force: 2021 IECC with Massachusetts amendments (780 CMR chapter 11R, 10th edition)
In force since: 2024-10-11
Adoption: Statewide mandatory code
Municipalities may opt into the Stretch Code (225 CMR 22) or the Specialized Code (225 CMR 22 plus Appendix RC); they are a separate record.
The 10th edition has been the only edition in effect since the concurrency period ended 2025-06-30.
Verified against the state's own adopted rule or code-body page.

Governing body

State of Massachusetts

Region

Applies to

General contracting HVAC Insulation Electrical Windows & doors

Massachusetts Stretch and Specialized Opt-in energy codesMA-STRETCH

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