Home Energy Rating System (HERS Rating) & Stretch Energy Code

• Projected Rating – this is done from building plans and supplied material data to determine if the home/building will meet the Stretch Code, other applicable code requirements (IECC 2021) or energy efficiency goals. All HERS Buildings in the State of Massachusetts have a minimal score requirement of 42 or 45 per the MA Stretch Code Regulations. Maximum HERS ratings for renovations, additions, and change of use are less stringent.
• Site Review – on-site visual inspection (pre-drywall) of all systems, material, installation quality of insulation as well as modify rating based on any changes made from original plan information.
• Confirmed Rating – upon full completion of the home/addition a performance test is performed including Blower Door Pressure Test and Duct Air Leakage Testing. This test data is entered into the model and a Confirmed HERS Rating is provided to confirm the home/building did meet the Stretch Code, other applicable code requirements (IECC 2021) or energy efficiency goals.

Prescriptive Ratings are also available utilizing RESCheck software to help non Stretch Code projects meet the code requirements.

The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home's score the more energy efficient it is in comparison to the HERS Reference Home.

Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20% more energy efficient.

Stretch Code By Community (Map)

Stretch Energy Code Summary

Mass.Gov Energy Rebate Page