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Massachusetts will complete implementation of the 2018 IECC on Nov. 7, 2020

2018 IECC – 2 Major Changes

Massachusetts will complete the implementation of the 2018 IECC on November 7, 2020. All projects that received permits between February 7, 2020 and November 7, 2020 can apply either the MA amended 2015 IECC or the MA amended 2018 IECC. Permits issued after November 7, 2020 are subject to compliance with the MA amended 2018 IECC.

There are two major changes between the 2015 and 2018 editions of the code that affect blower door testing and ventilation requirements.  The blower door target of 3 ACH50 remains the same here in Massachusetts, what changes is that each dwelling unit must pass on its own.  In multi-family housing, we have previously been able to “guard test” the units by depressurizing the adjoining units, effectively negating any leakage between units. This test method is no longer available and builders should be aware so they can address the air sealing details early in the build process with either traditional methods or new technology like AeroBarrier. To learn more about AeroBarrier, visit

Ventilation requirements have been eased slightly, essentially back to the ASHRAE 62.2 – 2010 version.  This will reduce the required CFM of ventilation in homes, particularly multi-family homes.  For builders of larger homes who were using multiple pieces of ventilation equipment, these homes may be able to get by with one ventilation source -talk to your rater to find out the ventilation requirements for your specific project.  Home Energy Raters, LLC continues to recommend the use of heat recovery or energy recovery ventilators in all projects as these units have multiple benefits and can be cost-effective.

If you have questions about how these changes will affect your current or future projects, give us a call at 508-833-3100.