Not sure which energy code requirements apply to your project? Find out!

North Attleborough is a Stretch Energy Code Community.

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What does this mean?

In 2009, Massachusetts became the first state to adopt an above-code appendix to the base building energy code known as the Stretch Code. The Stretch Code, which emphasizes energy performance as opposed to prescriptive requirements, is designed to result in cost-effective construction that is more energy efficient than that built to the mandatory state-wide IECC base code.

Stretch Code Compliance:

In order to meet the requirements of the Stretch Code, builders must hire a certified HERS Rater, like Home Energy Raters, to perform a series of tests (HERS Rating) to determine if the home meets energy code compliance. The Stretch Energy Code (2021 IECC w/ MA Amendments) has changed as of January 1, 2023, for residential buildings 3 stories or less. 4+ story residential buildings will remain on the current code until the 2023 Multifamily & Commercial Code goes into effect on July 1, 2023It is important to note that there is no grace period with the new code changes.

This new Energy Code brings some substantial updates/changes which may affect how you build. There is an overall push to remove fossil fuels from new buildings and higher HERS Ratings will be allowed for all-electric buildings.

HIGHLIGHTS OF CHANGES (applies to both new construction AND renovation/addition projects):

– HERS 52 required if any propane or natural gas is used in the building
– HERS 55 allowed if the home is all-electric
– HERS 55 (Fuel + Solar) or HERS 58 (Electric + Solar) also allowed
– 1 EV-Ready space and wiring per house required (EV-Ready also required for multi-family projects but requirements vary)
– ERV or HRV will now be required. Bath fans no longer meet the requirement for whole- house mechanical ventilation. There are some models we recommend using (with lower wattage) that help the HERS Rating, but you can use any brand you would like. You will still need to meet the required CFM of ventilation.
– HVAC duct leakage testing is now required for all systems, even if all ducts are within the conditioned envelope
– HERS Ratings will be required for additions over 1,000 sq ft and/or over 50% of the original structure (Level 3 Alteration per IEBC)
– Starting July 1, 2023, municipalities can vote to approve the “Specialized Stretch Code” which will require Net Zero/Zero Energy, solar, and lower HERS Ratings. Municipalities that opt-in to this are likely to provide a 6-9 month grace period. We will make sure to let you know when we hear of municipalities approving this provision.


– On July 1, 2024, HERS requirements drop to HERS 42 for buildings with any gas/fuel or HERS 45 for all electric homes/buildings

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The following municipalities have adopted this new specialized Stretch Code:

Effective 7/1/23: Brookline, Cambridge, Somerville, Watertown
Effective 1/1/24: Action, Aquinnah, Arlington, Boston, Concord, Lexington, Lincoln, Maynard, Newton, Northampton, Sherborn, Stow, Truro, Wellesley, Wellfleet, Worcester

Specialized Energy Code Compliance:

Specialized vs. stretch code for muti-family homes

Our team is here to help you meet these new code requirements. Please call our office at 508-833-3100 or send us an email to to schedule a time to review your upcoming 2023-2024 projects. We will work with you to help value-engineer your projects and maximize any available incentives.