HERS Energy Rating System
HERS Index and related scales (From Wikipedia, “Home Energy Rating”)
Ratings provide a relative energy use index called the HERS Index – a HERS Index of 100 represents the energy use of the “American Standard Building” and an Index of 0 (zero) indicates that the Proposed Building uses no net purchased energy (a Zero Energy Building). The lower the value, the better.
For capitalizing a building’s energy performance in the mortgage loan, certification of “White Tags” for private financial investors, and by the US government for verification of building energy performance for such programs as federal tax incentives, the United States Environmental Protection Agency’s Energy Star program and the U.S. Department of Energy’s Building America Program.
The HERS Index was introduced in 2006 and replaced the earlier “HERS Score”, which ran in the opposite direction: The higher the value, the better. In 2009, the U.S. Department of Energy presented a new scale, the “EnergySmart Home Scale (E-Scale)”, “based on” the HERS Index, apparently simply by subtracting the HERS Index from 100. In this new scale, higher values correspond again to better performance.