Historically, smaller homes have been disadvantaged relative to the HERS Index ratings for average and larger homes.
Stakeholders seem pleased with the amendment, which incorporates a house size adjustment factor so that calculations are more accurate and result in a score that better reflects energy savings no matter the square footage.
“I am in favor of the change,” said Thom Marston, regional manager at Energy Services Group, a Maryland-based residential energy conservation company. “Anything that brings the standard to parity between small and large homes should be applauded. No building should have an unfair advantage over another.”
RESNET Executive Director Steve Baden says that the accredited HERS software programs used to calculate the scores must implement the change by July 1. All HERS raters must use the new version by Jan. 1, 2019, giving raters a transition period. RESNET plans to submit the amendment for the 2021 IECC codes cycle so the code will reference the updated standard.
For additional information about NAHB high-performance building initiatives, contact Jaclyn Toole at 800-368-5242 x8225.