RESNET Proposes Amendment on Building Size Adjustment to ERI Score

RESNET addresses concerns about the difficulty for smaller sized homes to achieve lower HERS scores.

RESNET will accept public comments on the proposed changes to preliminary draft addendum, PDS-04 of BSR/RESNET/ICC 301-2014 Addendum E-201x, Index Adjustment Factors, for 30 days beginning November 10, 2017 and ending December 10, 2017Comments will only be accepted on the changes to draft PDS-04 as indicated in the draft posted on RESNET’s website.


In the past there have been concerns expressed that it was more difficult for smaller sized homes to achieve lower HERS Index scores than it is for larger homes.

To address this issue the RESNET Standards Development Committee 300 authorized the release of a proposed standard amendment that incorporates a house size adjustment factor (BSR/RESNET/ICC 301-2014 Addendum E-201x, draft PDS-05).

The proposed Addendum E amends Standard ANSI/RESNET/ANSI 301-2014, Standard for the Calculation and Labeling of the Energy Performance of Low-Rise Residential Buildings using an Energy Rating Index, to incorporate Index Adjustment Factors for dwelling size and configuration in Energy Rating Index calculations.

Current Energy Rating Index calculations result in a disparity in the rating index for large versus small dwellings similarly equipped and configured for energy efficiency. Larger dwellings have lower energy rating index values than smaller dwellings. The purpose of the amendment is to establish an index adjustment factor methodology that adjusts the rating index for size and configuration in order that similarly configured and equipped dwellings of different sizes and configurations will achieve an equivalent energy rating index.

The RESNET Standard Committee 300 has approved submitting the proposed amendment BSR/RESNET/ICC 301-2014 Addendum E-201x, draft PDS-04, Index Adjustment Factors to the RESNET standard amendment public review and comment process.

CLICK HERE to access by the draft addendum comment page BSR/RESNET/ICC 301-2014 Addendum E-201x, draft PDS-05, Index Adjustment Factors.

Comments must be submitted using the Online Amendment Comment Form which is accessed from the comment page.

All comments are posted real time and can be accessed from the comment page.

The public comment period ends on December 10, 2017.

After the comment period, the RESNET Standard Development Committee 300 will consider and document each of the comments submitted and make appropriate changes. Any substantive changes to the draft addendum will be submitted for public review and comment.