When first getting into the realm of Home Energy Ratings, the lingo can be slightly confusing. HERS, the Home Energy Rating System is based on a home’s energy rating, which is an analysis of a home’s energy performance that includes energy modeling with accredited software. The HERS Rating is based on the HERS Index, the official number that comes from the rating. A home that just meets code has a HERS rating of 100. For every point above or below 100, the home is that many percentage points less or more efficient than the same home built to code. Lower numbers are better, they mean the house is more efficient. For example, a HERS Rating of 30 means that this home performs 70% better than the same home built just to code. A HERS Rating of 0 means it is a Net Zero Home which means it produces as much energy as it uses each year. 

How can you improve your HERS Rating?

A HERS Rater can do a comprehensive rating on your home to assess its energy performance. There energy rating will consist of a series of diagnostic tests using specialized equipment, such as a blower door test, duct leakage tester, combustion analyzer, and infrared cameras. These tests will determine the amount and location of air leaks in the building envelope. the amount of leakage from HVAC distribution ducts, the effectiveness of insulation inside walls and ceilings, and any existing or potential combustion safety issues. Some other variables that are taken into account include floors over unconditioned spaces (like garages and cellars), attics, foundations, and crawlspaces, windows and doors, vents and ductwork, water heating system and thermostats. These tests will allow you to fix any problems that may be decreasing your HERS Rating. Using these tests will give insight into potential issues in your home. For more information on common issues during the building process, check out our other articles on Building Sciences. 

Once the test have been completed, a computerized simulation analysis using RESNET Accredited Rating Software will be used to calculate a rating score on the HERS Index. 


Whether building a new home, remodeling an old home, or if you are just curious about the rating and efficiency of your home, the HERS Index is one of the most widely known and used tests around.