HERS is a Home Energy Rating, established by the Residential Energy Services Network (RESNET). It is a measurement of a home’s energy efficiency. It allows buyers to compare the energy efficiency of different homes. With the HERS index, the lower the score the less purchased energy is needed.
The HERS Reference Home has a HERS Index of 100, representing the energy use of a home built to current energy codes; an Index of 0 (zero) indicates that the home uses no net purchased energy (a “Zero Energy” home, (ZEH or ZEB). A home we completed in May 2009 received a HERS index of 52, and we have identified changes that will help us achieve an even lower index.
Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus, a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home, and a home with a HERS Index of 80 is 20% more energy efficient.
In climate zone 6, a HERS index of 80 is required for Energy Star accreditation.