The Commonwealth of Massachusetts is taking bold steps to combat climate change, with ambitious goals to slash greenhouse gas (GHG) emissions by 50% by 2030 and achieve net-zero emissions by 2050. A key part of this strategy focuses on buildings, which account for nearly 40% of GHG emissions in the U.S.
Enter the new 10th Edition Stretch Code and Specialized Code – game-changing regulations that are reshaping the landscape of building design and construction in Massachusetts. These codes introduce rigorous targets for envelope thermal performance, energy efficiency, and electrification, affecting both new construction and renovation projects across commercial and residential sectors.
Three Tiers of Energy Code
The 10th edition Massachusetts Building Energy Code introduces a three-tiered approach:
- Base Code: Applies to municipalities not part of the Green Communities program.
- Stretch Code: Mandatory for all Green Communities.
- Specialized Code: An opt-in code for municipalities seeking even higher standards.
The Stretch and Specialized Codes are detailed in 225 CMR 22.00 (for residential low-rise construction) and 225 CMR 23.00 (for commercial and most multifamily buildings).
Specialized Code: The Next Level
For communities ready to push the envelope further, the Specialized Code mandates additional criteria for building electrification and on-site renewable energy. Pioneering cities like Brookline, Cambridge, Newton, Somerville, and Watertown have already adopted this code, with more expected to follow suit.
Energy Modeling: A Critical Tool
The Stretch Code offers five energy performance pathways, tailored to a project's size and type. These include prescriptive, targeted performance (TEDI), relative performance, Passive House certification, and HERS rating pathways. Most large commercial projects (excluding labs) will need to meet TEDI requirements or achieve Passive House certification.
Importantly, most projects will require energy modeling to demonstrate compliance. Given the challenging nature of these new efficiency requirements, design-assist modeling is highly recommended from the outset to ensure project success.
Farewell to All-Glass Buildings
The days of all-glass buildings in Massachusetts may be numbered. The 10th edition Stretch Code introduces ambitious thermal performance targets for building envelopes. These apply to above-grade vertical envelopes and include specific U-factor targets for vision glass and area-weighted U-factor targets for the full assembly. An "envelope backstop calculation" is required to evaluate the full envelope's thermal performance, which must be submitted to the Massachusetts Department of Energy Resources (DOER) as part of the building permit application.
Aligning with Municipal Regulations
Many Massachusetts municipalities have established their own building decarbonization policies. For example, Boston has implemented Zero Net Carbon (ZNC) zoning and Building Emissions Reduction and Disclosure (BERDO) requirements. The good news is that compliance with the 10th edition Stretch Code and Specialized Code will, in most cases, help projects meet these additional municipal regulations.
In conclusion, Massachusetts is setting a new standard for building energy efficiency and decarbonization. As these codes reshape the built environment, they're not just an afterthought – they're driving design from the ground up. For building professionals and property owners in the state, staying ahead of these changes will be crucial for success in the coming years.
Massachusetts Energy Code Website
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