Massachusetts Stretch Energy Code to Expand: What Does it Mean for You?

By Kevin Pink, Marketing and Development Specialist

Have you heard of the Massachusetts stretch energy code? Are you wondering what it is, and whether you need to think about it for new homes being built? Read on to expand your knowledge of stretch code, and what the coming changes mean for you!

Massachusetts has a base energy code that all buildings in the state must follow. It is based on the International Energy Conservation Code (IECC)’s most current version and specifies certain standards that all building projects must achieve regarding their energy consumption.

The stretch code is an initiative adopted by many towns across Massachusetts requiring buildings to meet higher energy efficiency standards.

As of October 26, 2016, 186 Massachusetts cities and towns have adopted the stretch code- take a look at the map and list to see if your town is on it! As of January 1, 2017, twelve more towns in central and western MA will officially mandate the stretch code:













If my town has adopted stretch code, what does it mean for me?

Residents: it means that if you are building new or renovating it must be in accordance with certain energy efficiency standards. The stretch code has stricter standards for new residential construction and renovations/additions.

The stretch code takes a “performance approach”, which looks at the overall efficiency of the home as opposed to requiring minimum efficiency targets for each design element such as windows, insulation, heating system, etc. New residential construction requires a Home Energy (HERS) Rating, including two inspections using the Energy Star Qualified Homes Thermal Bypass Checklist. For new homes permitted in any stretch code town on or after January 1, the maximum HERS index allowed will be 55.

updated-hers-indexEnergy efficiency is measured by a building’s HERS index, which is the nationally-recognized industry standard for calculating energy performance. The HERS index spans from 0 to 150, with a home constructed to the MA base code standard after 1/1/17 falling at about 75. A lower score indicates the percentage of improvement over the base code, so for example, a HERS rating of 55 means the home is 20% more efficient than a new home built to the base energy code in Massachusetts.

Renovations and additions to existing homes have an option to follow the performance approach (requiring a HERS rating) or the “prescriptive approach”, which requires a specific set of energy efficiency improvements (e.g., insulation rated to a specific R value, ENERGY STAR-compliant windows). Renovations in commercial buildings have less strict efficiency requirements than new construction as well, due to the design constraints often imposed by working with existing buildings.

Contractors: Your projects must comply with  the code’s efficiency standards, and depending on whether they are new construction or renovations, may require a HERS rating. For assistance helping your clients achieve energy code standards, contact CET’s High Performance Building experts. They have the knowledge, skills, and equipment to help you build with accordance to either the base energy code or the stretch energy code, and may be able to help your client take advantage of incentives through Mass Save’s New Construction and Major Renovation program.

If you’re already familiar with the existing stretch code, you may want to learn how it will become stricter on January 1. Our experts are offering several training sessions in the next three months to help you get up to speed on the changes and provide practical solutions to help you meet the new standards. Sign up today!


  • Hi,
    I have heard that the new 2017 MA building code is very like the stretch code. If true it will be easier to get South Hadley to join Green Communities. True?


    John Howard
    15 The Knolls Rd.
    S. Hadley, MA 01075

    January 23, 2017
    • Kevin Pink

      Hi John,

      Thank you for your question!

      By definition, the stretch energy code is designed to require greater efficiency through more aggressive energy use measures. The Massachusetts Office of Public Safety and Security ( regulates the Board of Building Regulations and Standards, which is responsible for setting the building codes in Massachusetts, and is best equipped to answer questions regarding the differences between base and stretch energy codes. Your local building inspector may also be able to address your questions.

      Additionally, the Green Communities Designation and Grant Program (, as administered by the Massachusetts Office of Energy and Environmental Affairs, helps municipalities take the steps to achieve the Green Community designation.

      Thank you again for your question!


      Kevin Pink
      Marketing and Development Specialist
      Center for EcoTechnology

      January 24, 2017
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