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Implementation of ANSI RESNET Standard and New Quality Assurance Procedures on October 1, 2015 Will Effect HERS Index Scores

May 26, 2015

Because of the adoption of the ANSI-RESNET Standard 301-2014 and new RESNET quality assurance procedures, there will be changes in HERS Index Scores beginning on October 1, 2015.

To determine the potential effects of the upcoming changes to HERS Index Scores, RESNET commissioned IBS Advisors to complete an analysis.

The study reports that the implementation of ANSI/RESNET Standard 301-2014 this year will cause HERS Index scores to increase by an estimated 2 to 3 points due to infiltration and ventilation changes, and to decrease by an estimated 3 to 6 points due to changes related to efficient domestic water heating. This will result in a net benefit to energy efficient builders of 1 to 3 points in HERS Index Scores over the current calculations.

RESNET accredited HERS software programs must incorporate these changes by August 1, 2015.

In 2013 RESNET started to improve the quality assurance standards and procedures at the request of large national production builders who were legitimately concerned about the integrity and consistency of the HERS Index Scores nationally. These builders have heavily invested in the use of the HERS Index for marketing and in HERS Raters performing energy code compliance and tax credit verifications.  These efforts culminated in a set of RESNET policies that were adopted by the Board of Directors and the creation of a balanced ANSI Standard Development Committee to oversee the development of implementation standards to carry out those policies.  Some of these policies target specific practices through increased validation checks in RESNET accredited HERS Software programs for reasonability.  These actions were taken to clearly define the boundaries on data that HERS Raters can input into the rating software programs.

In the past, RESNET’s standards and procedures allowed too much flexibility in the software inputs of accredited rating software programs which resulted in inconsistencies between software tools and raters. In some cases, this led to HERS Index Scores that were lower than they should have been.   RESNET addressed the issue of unrealistic data entry in the HERS software programs by creating a set of internal bounds checks that must be incorporated by all RESNET accredited software tools by August 1, 2015. These checks will result in rejecting unrealistic data entries and flagging questionable entries for review by the Quality Assurance Designee and RESNET staff.

The study reports that HERS Index scores for builders whose raters made data entries that were questionable may go up an average of 7 points once the new RESNET quality assurance policies are implemented and the software bounds checks are in place.  This issue is HERS Rater specific.  The report provides its analysis in aggregate and does not report on specific builders or HERS Raters.

The report can be downloaded at Upcoming Changes to the HERS Index and Potential Impact on HERS Index Scores

The inconsistencies documented in this analysis represent a small percentage of homes rated in the United States.  RESNET has no evidence of wrongdoing in the current boundaries set by HERS software providers, nor of HERS Raters applying interpretations of the reasonability of data entries.

To allow builders an opportunity to adjust to the changes addressed in the report, the RESNET Board of Directors has moved the date when the revised software programs must be used by HERS Raters to October 1, 2015.

After the revised HERS software programs become available after August 1, 2015, HERS Raters are encouraged to work with their builder clients to determine how the changes will specifically effect their scores.