The HERS INDEX as explained by RESNET

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.What does a HERS rating say about a 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.

How does the HERS Index work?

  • 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.
  • The U.S. Department of Energy has determined that a typical resale home scores 130 on the HERS Index while a standard new home is awarded a rating of 100.
  • 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

More on what 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.

Some of the variables included in an energy rating are:

  • 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.

High Performance Home Tech Talk

Welcome to the Build Omaha Certified High Performance Home Blog.  My name is Jesse Krivolavek and I am a building scientist with experience testing over 4,000 homes.  I am delighted to serve as the moderator and bloggerator for all things that impact performance, building science and energy efficiency in new homes.

We will start with introducing the Certified High Performance home Program.  The program is sponsored by Build Omaha and is a recognition, marketing and training program.  The website is and here are a few fun facts about the program:

  • Certified High Performance Homes EARN a HERS Index of 65 or lower during a Third-Party Certified HERS Rating.
  • A Certified High Performance Home is built by a HIGH QUALITY BUILDER that undergoes continuous training in climate zone specific building science, current best practices and the HERS INDEX.
  • Certified High Performance Homes are DESIGNED to use at least 35% less energy than the average similar new home and 50% less energy than a similar existing home.
  • In addition to using LESS ENERGY to lower operating costs and reduce environmental impacts, Certified High Performance Homes are built to have better air quality, durability and comfort.
  • A Certified High Performance Homes has a HERS Rating label and national recognized documentation (40% of all new homes in the U.S. were HERS Rated in 2011).
The next topic will be on "What the Heck is a HERS Rating" . . . but I would like to encourage anyone wanting to know more about building science, home performance or energy efficiency, to please submit topic requests.