Ensuring compliance meeting the Massachusetts stretch code

Activists sued the Commonwealth of Massachusetts in 2016 for not being on track to meet climate change targets as required by the state’s 2008 Global Warming Solutions Act. This ignited a flurry of actions by the state, including the enactment of the 2021 Next Generation Roadmap Act and greenhouse gas emission targets for many sectors, including buildings.

Massachusetts has now implemented more stringent building energy codes. Because of its electrification strategy, including a decarbonization of the electric grids, the new codes have focused primarily on reducing heating loads.

A Complex Code Landscape 
The state’s baseline mandatory code is de-rived from the 2021-IECC, but there are two optional overlays that local jurisdictions can choose to adopt: The Stretch Code and the Specialized (Net-Zero) Code. Few municipalities use just the base code. Currently, more than 90% of the population is covered by the Stretch Code, and 29% is covered by both the Stretch and Specialized Codes. 

There are five different compliance paths:

•    Home Energy Rating System – for residential buildings;
•    Passive House Certification – for residential buildings, but allowed for any building;
•    Targeted performance path – for larger residential buildings and most nonresidential buildings;
•    Relative performance path – for high internal load buildings like laboratories and hospitals only; and
•    Prescriptive path, which also includes a component performance alternative – for small nonresidential buildings only.
To minimize heating, Massachusetts prioritized preserving vertical envelope performance. This eliminates trade-offs with horizontal envelope, HVAC systems and lighting in the targeted and relative performance paths and in the prescriptive path component performance alternative. Thermal bridges must also be accounted for, and air filtration is minimized in all paths.