Home Energy Rating and the HERS Index

We've thrown around the term "home energy rating," particularly in our articles about the CBPCA and The US Department of Energy.  But, without proper context, the phrase probably has little meaning to those of us that aren't in the energy saving industry.  Since we here at buildaroo.com are all about Making Green Easy, let us take the time to explain.

A home energy rating, at its simplest, analyzes your home's energy efficiency and translates that into a score known as a "HERS rating."  This score is based on a home's construction plan and on site inspections, and is carried out by a certified Home Energy Rater.  The Home Energy Rater uses a software package that analyzes the energy efficiency of your home, based on the construction plan you provide.  The rater projects a score pre-construction, and then once your home is built the rater identifies any improvements that can be made to boost the home's score.  Once this process is complete, the rater conducts some on site tests to determine the home's final HERS Index Score.

This index was developed by RESNET, the Residential Energy Services Network.  It compares your home to a home built to the specifications of the HERS Reference Home.  A home built to the specs of the HERS reference home would score a HERS Index of 100 (This is not so good).  A home that produces as much energy as it uses, or a net zero energy home, would score a HERS Index of 0 (this is pretty tough).  Most homes built with the help of a rater score between 40 to 80 on the scale.  A home that scores 40 on the scale is 60% more energy efficient than the HERS Reference Home.

This HERS Index Score is the national standardized evaluation of a home's energy efficiency.  When done right, it can help a home owner meet the Energy Star standards for home energy efficiency, qualify a home owner or buyer for an energy efficient mortgage (EEM) or an energy improvement mortgage (EIM).

Still interested in HERS rating and home energy efficiency?  Check out some of the following resources: