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Cracking the Massachusetts Energy Codes

Introduction

Four heads are better than one.

On December 23rd, 2022, the clock started ticking for the architectural community when the DOER released a final version of the updated Massachusetts Stretch Code and the new Specialized Opt-in Code. Knowing that the changes would be significant, various taskforces were created by Alison Nash of Sasaki. A “Decision Tree” taskforce was established in January of 2023, and includes Sustainable Design Leaders, Gabrielle Aitcheson of ICON, Suni Dillard of HMFH, Lauren Günther of DiMella Shaffer, and DiAnn Tufts of PCA. 

The Sustainable Design Leaders is a national peer network group that connects passionate sustainability advocates. Given that each of our offices has expertise in various project types, we were able to bring different perspectives to the table. In 2023, the group dissected the newly released energy code language, mapping the trees and branches of each compliance path while also providing QA/QC. With the February 2025 DOER amendments and April 2025 BBRS amendments, the decision trees were revisited and updated to reflect the latest requirements. 

The result of our collective analysis is the creation of (2) main decision trees and (10) branches.  

Main Decision Tree: New Construction (Link)	Main Decision Tree: Existing Construction (Link)
New Construction Branches:	Existing Branches:
Low-Rise Residential, Less than 12,000 SF	Existing Low-Rise Residential Base Code
Low-Rise Residential, Greater than 12,000 SF	Existing Low-Rise Residential Stretch Code
Commercial, Residential, 4 stories or more	Existing Commercial Base Code
Commercial, Nonresidential, Less than 20,000 SF	Existing Commercial Stretch Code
Commercial, Low Ventilation, Greater than 20,000 SF
Commercial, High Ventilation, Greater than 20,000 SF

 

September 2025 Decision Tree Updates: 

• Aligned with DOER amendments dated 02/14/2025 and BBRS amendments dated 04/29/2025. 

• Changes to decision trees primarily affect residential and existing construction. 

• “Draft” removed from base code branches and updated to reflect finalized base code language. 

• Existing construction branches now separate the base code branches for clarity. 

• The Specialized Opt-in Code applies only to new buildings and not to additions, regardless of size. 

• Pathways defined for first-time tenant fit-outs when the core and shell is built under the previous energy code versus the current code. 

• Clarified parking garages greater than 20,000 sf pathway exception. 

• Removed the “Until 2024 Only” and “after July 2024” distinctions, as they are no longer applicable. 

• Added HERS Index score option with embodied carbon compliance. 

 

Decision Trees + Branches 

Changing systems need a roadmap.  

Below is an outline of the overall concept, how to navigate the decision trees, and what to pay attention to. These decision trees were first created in 2023 and have since been updated to reflect the February and April 2025 Energy Code Amendments. 

Here’s what the decision trees do: 

• Broadly show the difference between the Base Energy Code, Stretch Code, and the Specialized Opt-in Code. 

• Act as a quick reference to identify key decisions and options for compliance. 
• Reference code sections related to each path. 
• Provide “fun facts” to help guide the process.

 

Here’s what the decision trees do not do: 

• Do not explain what is in each referenced code section. 

• Do not provide every referenced code section. 

• Do not provide definitions for all terms used. 

• Do not include other codes or ordinances. 
• Do not guarantee alignment with the Authorities Having Jurisdiction (code officials). 

 

How the decision trees work: 

• Start with the “New Construction” or “Existing Construction” decision trees and answer the questions to determine which branch to follow. 

• Use the branch to determine the appropriate path or path options for your project. 

• The identified path is the starting point to communicate with all those involved in the project and confirm interpretation with code officials. 

 

What to pay attention to: 

• Know what code is being used by the municipality; refer to map blog post. 

• One “Use” and/or “Existing Building Scope” at a time. 

• Cross reference with the “Municipal Fossil Fuel Free Building Demonstration Program” and other relevant ordinances. 

• All optional pathways are indicated even if the pathway would not be typically used. 

• Our focus is on understanding the intent of the code, not a specific interpretation. 

• All buildings in MA Stretch Code communities, including buildings under 100,000 square feet, are required to follow the Stretch Code. This also includes existing and low-rise residential buildings. 

• The decision trees and branches are for educational purposes. * 

• Updates will occur from time to time, but the link will remain the same. Note the version date in the file name and on individual pages (the current version reflects the February and April 2025 Amendments). 

 

Conclusion  

We need to learn to crawl before we can walk.  

The decision trees and branches were always intended as a foundational tool—graphic, easy-to-understand diagrams that can help design teams, clients, contractors, and code officials navigate complex (and ground-breaking) energy codes. Just as the codes evolve, so too do the decision trees. What began in 2023 has now been revisited and updated to incorporate the February and April 2025 Amendments, reinforcing our commitment to keeping this resource current and relevant.  

Our goal is to continue outreach to the greater community. Post contributors include Gabrielle Aitcheson of ICON, Suni Dillard of HMFH, Lauren Gunther of DiMella Shaffer, and DiAnn Tufts of PCA. Please reach out to any of us if you would like to learn more about the decision trees. 

We aim for the community to spend less time understanding the changes, and more time applying the energy code. The information contained herein is for educational purposes only and does not guarantee accuracy of the information as it relates to State energy codes or other local and regional energy and sustainability requirements, or the interpretation and application of those requirements. Please consult official documentation from State and Local agencies as applicable.