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What Is the HERS® Index

The Home Energy Rating System (HERS) Index is the industry standard by which a home’s energy efficiency is measured. It’s also the nationally recognized system for inspecting and calculating a home’s energy performance.

The HERS® Index measures a home’s energy efficiency and there are a lot of great reasons to have a home energy rating performed on your house.

It can tell you so much about the home you live in, like how efficiently it’s operating and where you can make modifications for greater energy savings. When you’re selling your home, a low HERS® Index Score can command a higher resale price. And when you’re buying a home you can anticipate the costs of energy bills and efficiency upgrades.

A certified Home Energy Rater assesses the energy efficiency of a home, assigning it a relative performance score. The lower the number, the more energy efficient the home. A typical home built to 2006 energy efficiency standards scores 100 on the HERS® Index.

  • A home with a HERS® Index Score of 70 is 30% more energy efficient than a standard new home
  • A home with a HERS® Index Score of 130 is 30% less energy efficient than a standard new home

What do the scores mean?

To calculate a home’s HERS® Index Score, a certified RESNET HERS® Rater does an energy rating on your home and compares the data against a ‘reference home’– a designed-model home of the same size and shape as the actual home, so your score is always relative to the size, shape and type of house you live in.

  • All exterior walls (both above and below grade)
  • Floors over unconditioned spaces (like garages or cellars)
  • Ceilings and roofs
  • Attics, foundations and crawlspaces
  • Windows and doors, vents and ductwork
  • HVAC systems, water heating system, and your thermostat

RESNET has created a National Registry that contains information on certified RESNET HERS® Raters and Home Energy Ratings. If you would like to confirm if a HERS® Rater’s certification is in good standing or check the HERS® Index Score of a home, this is the site for you.

The public can now access the following information on certified HERS® Raters:

  • The name of the certified HERS® Rater
  • The rating company name
  • Location of the rating company
  • Name and contact information of the rating quality assurance provider that certified the Rater and is responsible for the quality assurance oversight
  • Whether the Rater is active or has the certification been suspended or revoked

Click on RESNET National Registry to find out about certified HERS® raters.

The public can now access the following information on rated homes:

  • Address of home rated
  • Name of rating company that rated the homes
  • Date that rating was completed
  • HERS® Index Score of home

Click on RESNET HERS® Index Score Information to get details on HERS® rated homes.

Scroll through the numbers and see how the scores relate to homes and energy savings.

A lower score means a more affordable, comfortable and energy efficient home.