The HERS Index

The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home's HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.
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.

Choosing a Rater

As in any trade, all raters are not the same. Raters have different experience, training and skills. You should not select a rater based solely on price. The following are issues to consider when choosing a home energy rater to work with:

• Find out what are the basic services the rater provides. RESNET has adopted a Rating Standards of Practice to define this.
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  Determine what training and experience the rater requires to meet your needs. In addition to receiving a rating score, will you require design assistance, HVAC sizing calculations, or construction crew training? Be sure you know that the rater's skills meet your needs.