303 Technical Requirements

HERS Update to Standard ANSI/RESNET/ICC 301-2022

MINHERS Addendum 42 adopted Standard ANSI/RESNET/ICC 301-2022 to replace Standard ANSI/RESNET/ICC 301-2019 as the basis for calculation of the HERS rating. Use of software accredited to comply with ANSI/RESNET/ICC 301-2022 and the requirements listed below is mandatory based on building permit date. The Mandatory Compliance Date is July 1, 2025.

303.1 Applicable Standards

All RESNET Home Energy Ratings conducted in accordance with this Standard shall comply with the provisions of ANSI/RESNET/ICC 301, Standard for the Calculation and Labeling of the Energy Performance of Dwelling and Sleeping Units using an Energy Rating Index and its MINHERS adopted addenda.

Exception 1: RESNET Home Energy Ratings conducted in Puerto Rico and the US Virgin Islands shall comply with the provisions of ANSI/RESNET/ICC 301, except that Ratings of homes are permitted to use a default infiltration rate of 10 ACH50 in lieu of conducting an airtightness test in accordance with Standard ANSI/RESNET/ICC 380. In addition, for a home in the Tropical Climate Zone for which its Living Space is not serviced by a space heating mechanical system and not more than one-half of its Living Space is serviced by a space cooling mechanical system, the Conditioned Space Volume shall be defined as the volume of its Living Space and the Conditioned Floor Area shall be defined as the floor area of its Living Space.

Exception 2: RESNET Home Energy Ratings shall be calculated using the modifications of ANSI/RESNET/ACCA/ICC 310-2020 established by Addendum 53f. (See Addendum 53f).

NOTE: Addendum 89i is currently in effect.

Exception 3: Sampled Ratings for Townhouses and Detached Dwelling Units are not permitted. For Sampled Ratings of Attached Dwelling Units, the requirements of MINHERS Chapter 6 shall supersede the requirements of ANSI/RESNET 301-2022, Section 7.1.4.4.

NOTE: Addendum 71 is currently in effect.

Exception 4: Home Energy Ratings shall be calculated using the modifications of Standards ANSI/RESNET/ICC 301 established by MINHERS addenda:

• Addendum 66, CO₂e Index
• Addendum 71, SEER2/HSPF2
• Addendum 81, Supplemental Criteria for Adoption of ANSI/RESNET/ICC 301-2022

303.2 Rating Registration

All Confirmed, Threshold and Sampled HERS Ratings shall be registered with the National RESNET Registry in accordance with Sections 102.1.4.10 and 102.1.4.12.

303.3 HERS Rating Tools

All RESNET-accredited HERS Rating Tools shall prohibit printing of Confirmed, Threshold and Sampled HERS Ratings until such rating has been registered with the National RESNET Registry and a unique registration identification has been assigned. Said registration identification shall be prominently displayed on all printed HERS Rating reports.