HOME ENERGY RATING SYSTEM (HERS)
The E+ Green Building program requires buildings that generate more energy than they use annually as indicated by a HERS Index of less than zero.
Developed by the Residential Energy Services Network, the HERS models building energy performance. A comparable home, the HERS Reference Home, which is built to the specifications of the 2006 International Energy Conservation Code, scores a HERS Index of 100.
A Net Zero Energy home scores a HERS Index of zero and an E+ Green Home scores a negitive HERS Index. Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. An Energy Star home must have a HERS Index of 85, or lower, and is 15% more energy efficient than the HERS Reference Home.