The Massachusetts Residential Stretch Code will update on January 1, 2023, with all projects permitted on or after that date being subject to the new requirements. There will be no concurrency period. The updated Massachusetts Commercial Stretch Code will become effective July 1, 2023. Training courses on the new residential and commercial stretch code are under development, but in the meantime, we’ll use this newsletter to communicate important changes to the stretch code. Three Tiers of Energy Code in Massachusetts Base Energy Code As part of the Green Communities Act of 2008, Massachusetts is required to update its building code every three years to be consistent with the most recent version of the International Energy Conservation Code (IECC). In 2022 the Board of Building Regulations and Standards (BBRS) plans an update of the full set of building codes to the MA 10th edition based on the ICC 2021 model codes. This includes an update of the base energy code to the IECC 2021 with MA amendments. Stretch Energy Code DOER, in consultation with the BBRS, has updated the Stretch Energy Code (225 CMR 22 &23) which is a key requirement for municipalities that are Green Communities. Municipal Opt-In ‘Net-Zero’ Specialized Stretch Code (new!) A new climate-focused energy code option was created by the 2021 Climate Act. DOER developed this new code alongside the Stretch Energy Code update. What does this mean for stakeholders in Brookline? Unlike the other building code updates, this Code must first be adopted locally. The Select Board may decide to hold a Special Town Meeting on January 10, 2023, at which point Town Meeting Members will vote on whether or not to adopt this code. If voted, the Specialized Code would likely go into effect July 1, 2023. PLEASE NOTE: The Select Board will hold a public hearing on December 20th; please refer to the Town Calendar for any other public hearings as they are scheduled. If the Special Town Meeting moves forward, files will also be uploaded by the Select Board’s office to the Town Meeting webpage. The final specialized code language includes: · net-zero building performance standards · a definition of net-zero building · designed to achieve MA GHG emission limits and sub-limits including a 50% GHG emissions reduction by 2030 from 1990 levels
HERS Index Changes for New Construction
One of the residential changes will be a reduction in the maximum Home Energy Rating (HERS) Index score, which will happen in two phases. Starting January 1, 2023, and effective through June 30, 2024, the maximum HERS Index for a mixed-fuel home will go down from the current HERS 55 to a HERS 52. (This reflects the change in the 2021 IECC where the Additional Energy Efficiency section requires a 5 percent decrease in the maximum Energy Rating Index.) Starting July 1, 2024, the maximum HERS Index score for a mixed-fuel home will drop to a HERS 42. All projects will be eligible for renewable energy offsets for onsite solar electric generation through June 30, 2024, but will be discontinued starting July 1. Please see the table below for more information.
| Maximum HERS Index Score (modeled without renewable energy) | | New Construction | Alterations, Additions, and Changes of Use |
| Until 1/1/23 | 1/1/23 through 6/30/24 | As of 7/1/24 | Until 1/1/23 | As of 1/1/23 | Mixed-fuel Building | 55 | 52 | 42 | 65 | 52 | Mixed-fuel Building with Solar Electric Generation | 60 | 55 | 42 | 70 | 55 | All-electric Building | 60 | 55 | 45 | 70 | 55 | All-electric Building with Solar Electric Generation | 65 | 58 | 45 | 75 | 58 |
HERS Index Requirements for Additions and Alterations
Starting on January 1, 2023, HERS Rating requirements will apply to some existing building projects for the first time. The requirements are as follows:
Additions - Additions over 1,000 square feet or exceeding 100 percent of the conditioned floor area of the existing dwelling unit must receive HERS Ratings and meet the maximum HERS Index scores in the Alterations, Additions, and Changes of Use column in the table above. Solar ready requirements will also apply for these types of additions.
- Additions that are 1,000 square feet or less will continue to follow base energy code.
Alterations
Projects with alterations meeting the International Existing Building Code (IEBC) definition of “Level 3” (over 50% of the home is renovated and reconfigured) and exceeding 1,000 square feet or 100% of the existing floor area must achieve the maximum HERS Index score in the Alterations, Additions, and Changes of Use column in the table above.
Additional updates to the stretch code starting January 1, 2023
Heat or Energy Recovery Ventilation (HRV/ERV) is required for all new homes. The HRV or ERV must also be tested by an independent third-party inspector using pressure pans or flow hoods.
One EV-ready parking space per home is required for one- and two-family dwellings and townhomes and the number of EV-ready parking spaces for new multifamily parking areas increases from 10% to 20% of parking spaces.
The optional Passive House Pathway will align with the most recent Phius standards, allowing the Phius CORE 2021 standard (efficiency) or the Phius ZERO 2021 standard (efficiency and renewable). The PHI standard remains unchanged as an option. 
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