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HERS® Standards

HERS® ratings are now based on Standards ANSI/RESNET®/ICC 301, ANSI/RESNET/ICC 310 and ANSI/RESNET/ICC 380 as adopted and modified by HERS Standards addenda that are incorporated into Chapter 3 of the HERS Standards. The heading on the first page of each Addendum identifies: the first date voluntary use is allowed, the Voluntary Compliance Date; and, the date compliance is required, the Mandatory Compliance Date.

Mandatory compliance with HERS Standards addenda is based on the building permit date or approved alternative dates. A home with a building permit date before the Mandatory Compliance Date does not have to comply. A home with a building permit date or on or after the Mandatory Compliance Date must comply. RESNET recognizes the following alternative dates to the building permit date: the date of the Certified HERS Rater’s or RFI’s first site visit; the date of the application of the permit; the date of the contract on the home; the date of an application for low-income tax credits or government administered competitive financing for a project meeting the State or local government definition for low income or affordable housing.

Currently both the Standards 301-2022, 310-2020 and 380-2022 suite of standards and the Standards 301-2019, 310-2020 and 380-2019 suite of standards are both authorized for HERS ratings. Use of the Standards 301-2022, 310-2020 and 380-2022 suite of standards will be mandatory for homes with building permit dates on or after January 1, 2027. Use of the Standards 301-2019, 310-2020 and 380-2019 suite of standards will not be allowed for homes with building permit dates on or after January 1, 2027. Ratings must be based on one suite of standards or the other. No mix-matching across suites is allowed.