Home >Articles >FREE Webinar – ERI and RESNET HERS® Index: Understanding the Differences

FREE Webinar – ERI and RESNET HERS® Index: Understanding the Differences

Nov 10, 2020

For HERS Raters and RFIs, understanding the differences between the HERS Index and the International Energy Conservation Code (IECC)’s Energy Rating Index (ERI) is critical to educating builders and code officials on their important differences.

The IECC’s ERI is a compliance pathway in the 2015, 2018, and 2021 versions of the IECC. The Home Energy Rating System (HERS) Index is a voluntary, national program used to rate the energy efficiency of homes. To date, there are over 2.9 million homes that have received a HERS rating. Although both HERS and the IECC’s ERI are largely based on the same American National Standard, ANSI/RESNET/ICC Standard 301, there are significant differences between these two programs.

Under the 2015 IECC, ERI and HERS were the same because there was no reference standard for calculating ERI scores. However, this changed under the 2018 IECC with the addition of ANSI/RESNET/ICC 301-2014 as the reference standard for calculating the ERI score and an amendment to R406.3 which changed the ventilation rate for the ERI reference home. The HERS Index does not incorporate the IECC amendment. This can create a significant difference in scores between the HERS Index and the IECC’s ERI. These two changes are just the tip of the iceberg when it comes to understanding the differences between HERS and ERI.

This webinar will clarify the differences between the IECC’s ERI scores and HERS scores to assist state and local code officials, builders, and HERS Raters/RFIs with understanding how each works.

Register here.