HERS Index & Energy Audits

The HERS Index is a scoring system established by RESNET (Residential Energy Services Network). A HERS Index of 100 is given to a home with specifications that match that of a HERS reference home that is based on the 2006 International Energy Conservation Code. The lower the home’s HERS Index, the more energy efficient it is compared to the HERS reference home. Each 1-point reduction in the HERS Index corresponds to a 1% reduction in the energy consumption and a 1% improvement in the energy efficiency of the home. Thus, a home with a HERS Index of 70 is 30% more energy efficient than the HERS reference home. A HERS Index of 0 would represent a home where renewable power generation is being utilized (such as solar energy) at a level where the energy generation matches the energy consumption of the home based on the HERS Index. These homes have implemented energy efficient features as well as renewable energy generation.

The Energy Rating Guide

The Building Energy Rating Guide is the official document generated as a result of the HERS energy rating. It contains a building rating scale illustrating the energy use of the rated home in comparison to the HERS reference home. It serves as an energy “yardstick”, much like the MPG rating does for an automobile. It allows one to compare the energy efficiencies of one home to another. The Building Energy Rating Guide also includes a bar chart, giving a numerical breakdown of the basic sources of energy costs for the rated home. It also shows the HERS Index and the star level of the home (5 Star+ being the highest level). If the rated home qualifies for an energy efficient mortgage (EEM), that is also illustrated on the Building Energy Rating Guide.

The Building Energy Rating Guide can be a very valuable document to the home owner if the HERS Index is low. It can be used to market and distinguish the home’s added energy efficiency features at the time of sale. Higher energy efficiency leads to lower ownership costs. This is turn makes the home more affordable to own.

An energy audit, also known as an energy assessment or survey, is exactly what you need when looking for ways to improve the energy efficiency of your home. A certified HERS Home Energy Auditor will use specialized equipment such as blower doors and infrared cameras to measure air leaks and reveal hard-to-detect areas of air infiltration and missing insulation.