osprey building performance

How it's done
The rating process starts with the rater thoroughly investigating the exterior conditions of the home and its interaction with outdoor conditions.
The rater then moves to the home's interior for some more measuring and calculating of the buildings properties.
Using the latest technology and techniques in home performance, the rater performs the required building and equipment diagnostics to determine the performance of the equipment and the tightness of the house.
The rater then enters all of the data into a computer program. The program compares the data from your house with a similar house using the standard construction to determine the rating.  If your home uses the same amount of energy, the rating is 100%.  If your home uses less energy, the rating is less than 100%.


The Home Energy Rating System, HERS® Index,
is the industry standard and nationally recognized system used for
measuring and calculating the energy performance of a home.

Home Energy Rating System

HERS® Index

HERS® Index
The HERS® Index was developed by the Residential Energy Services Network (RESNET®) to provide a consistent standard of verification of a home’s energy performance. The HERS Index is recognized by the Environmental Protection Agency (EPA) and the Department of Energy (DOE) as the official scale of home energy performance.

HERS® Rating

A HERS® rating is a standardized method of measuring the energy performance of a home that produces a numerical rating on the HERS® index scale. A rating of 100 indicates that the rated house uses the same amount of energy as a house of the same design using 2006 IECC standards of residential construction. The rating of 65 in the picture indicates that the rated house uses 65% as much energy as a house with the standard construction. A rating of more than 100 indicates that the house uses more energy than the house with the standard construction.  Most houses built before 2000 and many built later have a HERS® index rating of around 130 or more.