Home Energy Score VS Home Energy Rating System

The amount of money a home owner spends on utility costs to operate their house can have a significant impact on their monthly budgets.  Having a Home Energy Rating done on the home can help home owners figure out how efficient their homes are, and prepare for higher or lower costs than expected. There are 2 different types of processes to help home owners understand the efficiency of their energy usage in their homes.

The Home Energy Rating System (HERS) developed by the Residential Energy Services Network (RESNET) tallies a score based on an index where the lower the number, the more efficient the house. Using blower door testing and duct leakage tests, a HERS Rater compares the home being tested, to a reference home (a model home that is the same type, size, and shape) to base the score.

The HERS scale ranges from 0-100 with the average HERS score for a new home being 40. A home ranking 0 is considered a Net-Zero home, meaning it produces as much energy as it uses. A home compliant with the 2006 International Energy Conservation Code (IECC) would have a score of 100. To compare, the average home with a score of 40 is 60% more efficient than the 2006 IECC-compliant home.

The Home Energy Score (HES) was developed by the Department of Energy (DOE) and is another way to estimate a home’s energy usage. While the HERS scale is usually used for new homes, the HES scale is used for existing homes. The HES scale ranges from 1-10, with a higher score indicating a more energy efficient home. However, the HES estimates a home’s total energy use, not usage per square foot so larger homes tend to score lower. Using an assessor gathering around 50 data points like insulation grade, window type, and information on the heating/cooling system, the HES score is a gauge on how much energy the home might use.

The HES can be a great way to get an idea of a home-energy usage, which can help as a home owner prepares for a mortgage.  Because it indicates how energy efficient a home is, the lender could be more inclined to allow for a larger mortgage, knowing the owner is expected to have lower utility costs.

Although the HES is a low-cost and reliable way to get an idea of a home’s energy usage, it cannot be used to comply with the IECC. The Energy Rating Index (ERI) is used as a performance path to comply with the IECC. The HERS Index can be used for this performance path, so while more expensive than HES, it can be advantageous to builders in order to comply with the IECC.

Information Curated from nahbnow.com

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