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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  • Lawrence Davis

    I had my new home inspected by CETA and was told that my brand new appliances were not energy star. They were bought at Sears and say energy guide on them. Can I keep these?

    December 15, 2017
    • Kevin Pink

      Hi Lawrence,

      Thank you for your comment! We can see how this might be confusing, so hopefully this explanation offers a little more clarity. The Energy Guide sticker is a requirement mandated by the Federal Trade Commission, and must appear on boilers, central air conditioners, clothes washers, dishwashers, freezers, furnaces, heat pumps, pool heaters, refrigerators, televisions, water heaters and window air conditioners. The sticker indicates the projected annual energy cost one might expect for that product.

      ENERGY STAR is a project of the Environmental Protection Agency. ENERGY STAR uses independent third-party testing labs to certify specific models of appliances as more efficient than their peers, indicating which models are most likely to save energy and money for consumers. The ENERGY STAR label is a mark of distinction indicating that the appliance has achieved a standard of efficiency that puts it above others in its class.

      We hope this information helps clarify the difference between the Energy Guide and ENERGY STAR certification. Thank you again for your question!

      The CET Team

      December 18, 2017
  • Joel Mullett

    I recently had a home built in Lanesborough MA. I heard a lot of talk about stretch code. Certain requirements needed to be met for the HERS Rater.

    After inspection, the Hers rater said one of my bathroom exhaust fans needed to run 24/7 and the other needed to run 3 times an hour for 8-9 minutes per runtime.

    Question: How can this possibly be efficient. Wasted electricity and sucking heat out of my main living space going into my crawl space. Am I crazy for thinking this? Please let me know…

    Thanks Joel M

    January 5, 2018
    • Kevin Pink

      Hi Joel,

      Thank you for your question!

      The Stretch Energy Code requires that homes achieve a certain level of energy efficiency, so you are right that running those bathroom exhaust fans works against the goal! However, the Massachusetts Building Code also requires all new homes to have ventilation systems to change over the air in the house several times per day. You can do this with exhaust-only systems like bath fans or you can install more expensive (but more energy efficient) heat recovery ventilation systems to exchange indoor air and outdoor air. You have to install one or the other whether you build in a Stretch Energy Code town or not.

      Thank you again for your question!
      -The CET Team

      January 9, 2018

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