2018 IECC BASE ENERGY CODE

Massachusetts follows a base energy code that all new buildings must comply with. The code is based on the International Energy Conservation Code (IECC) and sets standards for energy efficiency, particularly focusing on the building envelope. As long as the mandatory requirements are met, projects can follow either the prescriptive or performance path to achieve compliance.

Performance Path Compliance:

The performance path allows for flexibility by using energy modeling to ensure the building uses equal or less energy than a home built to the prescriptive path. While this path requires a bit more effort, it offers the opportunity for cost savings by trading off expensive components in favor of others.

To comply with the Performance Path, you’ll need:

• Simulated energy performance analysis or Energy Rating Index (ERI) analysis.
• A HERS Rating is the most common and realistic method for this path.

We highly recommend the Performance Path with a HERS Rating as it provides flexibility, documented energy savings, and compliance with the energy code.

Prescriptive Path Compliance:

The prescriptive path requires specific building components, like insulation values and window performance, to meet exact standards outlined in the energy code. While this is a traditional and less complex approach, it doesn’t allow for flexibility in cost-saving options.

To comply with the Prescriptive Path, you will need:

• A REScheck certificate.
• Performance testing, including blower door tests, duct testing, and ventilation testing.
• Meeting the insulation and window performance specifications.

Note: This path is not eligible for Mass Save incentives.

As certified IECC/HERS Compliance Specialists, we help save time and resources by guiding you through the process and ensuring energy code compliance.

STRETCH ENERGY CODE

In 2009, Massachusetts introduced the Stretch Code, an appendix to the base energy code designed to improve energy performance beyond the minimum requirements. Stretch Code emphasizes energy efficiency, aiming for cost-effective construction with enhanced energy performance.

Stretch Code Compliance:

To meet the Stretch Code (2021 IECC with Massachusetts Amendments), builders must hire a certified HERS Rater to perform energy tests, such as a HERS Rating, to ensure the building complies. The Stretch Code saw significant updates in January 2023 and July 2024. For residential buildings 3 stories or fewer, new regulations now call for higher HERS Ratings and an increased focus on removing fossil fuels from buildings.

Highlights of Recent Changes (effective 2023 and 2024):

• Residential New Construction:
  • HERS 42 for mixed-fuel buildings.
  • HERS 45 for all-electric buildings with or without solar electric generation.
• Renovation/Addition Projects:
  • HERS 52 for mixed-fuel buildings.
  • HERS 55 for all-electric buildings with or without solar electric generation.
  • Electric Vehicle (EV)-ready spaces required for homes and multi-family projects.
  • ERV or HRV required for whole-house mechanical ventilation, with updated fan requirements.
  • HVAC duct leakage testing is now mandatory.

Many municipalities in Massachusetts have adopted the Stretch Code. View our interactive map to check if your area is included and learn more about the program.