Standard ANSI/RESNET/ICC 301-2019, Addendum A-2019 and Addendum B-2020 are adopted as the basis of the RESNET HERS by MINHERS Addendum 42. RESNET set the Mandatory Compliance Date (MCD) for Addendum 42 as January 1, 2021 but has now moved the MCD to April 1, 2021. Addendum 42 was adopted after ANSI/RESNET/ICC 301-2019 was amended to incorporate credits for HVAC quality installation grading based on ANSI/RESNET/ACCA/ICC 310-2020. The Software Consistency Committee chair advised RESNET that Software Tools revision and reaccreditation by January 1, 2021 would be difficult and requested that the MCD be moved to April 1, 2021. The RESNET Standard Management Board (SMB) approved this request, moving the date to April 1, 2021. What this means: HERS Ratings based on ANSI/RESNET/ICC 301-2019 are not required for Permit Dates prior to April 1, 2021. For Permit Dates beginning April 1, 2021, HERS Ratings must use software accredited under ANSI/RESNET/ICC 301-2019 with Addendum A-2019 and Addendum B-2020. Related note: All HERS Ratings for Permit Dates beginning January 1, 2021 must use hourly simulation. This date is not affected by the new MCD. While this change is necessary, RESNET understands that this delay can cause a challenge for HERS Raters and builders, who were expecting software to be available well before buildings receive their permits, so that they could design accordingly and offer Ratings for dwelling units in multifamily buildings over 3 stories. If you have feedback or suggestions on how RESNET can resolve specific issues you are experiencing, please submit them using the RESNET Standards Suggestion Box.