What is HERS Rating?
Developed in 2006 by RESNET, The HERS Index is the industry standard measurement of a home’s energy efficiency and is the nationally recognized system for inspecting and calculating a home’s energy performance. A certified RESNET Home Energy Rater assesses the energy efficiency of new homes and assigns them a relative performance score (the HERS Index Score).
The lower the number, the more energy efficient the home. A HERS rating reveals how efficiently a home is operating, where modifications can be made for greater energy savings and can anticipate the costs of energy bills and efficiency upgrades for new homes.
The U.S. Department of Energy has determined that a typical resale home scores 130 on the HERS Index while a home built to the 2004 International Energy Conservation Code is awarded a rating of around 100. To calculate a home’s HERS Index Score, a HERS Rater performs an energy rating on a new home and compares the data against a ‘reference home’ - a designed-model home of the same size as the home being rated. A home which scores a 60 on the HERS Index means that it is 40% more energy efficient than the baseline. A home which scores a 0 uses no net purchased energy and is considered a net zero home.
Why HERS Rating?
A comprehensive HERS home energy rating, conducted by a Certified RESNET Home Energy Rater, is the most in-depth energy performance assessment of a home that you can find. The comprehensive HERS rating provides a computerized simulation analysis utilizing RESNET Accredited Rating Software to calculate a rating score on the HERS Index. The report will also contain a cost/benefit analysis for the recommended improvements and expected return on investment. Mainly, it consists of diagnostic testing using specialized equipment, such as a blower door test, duct leakage test, combustion analyzer and infrared cameras to 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
Any existing or potential combustion safety issues
Other variables include:
Floors over unconditioned spaces like garages or cellars
Attics, foundations and crawl spaces
Windows and doors, vents, and ductwork
Water heating system and thermostats