Home Energy Rating System (HERS) Ratings

    HERS ratings predict a home’s energy consumption using software to evaluate building components in order to produce an objective index of energy usage.  Details of the home’s building characteristics, such as square footage, volume, insulation, air leakage, and mechanical equipment efficiencies are entered into REM/Rate computer software.  The software calculates the homes predicted energy usage, and compares it to a geometrically identical ‘reference’ home built to 2004 IECC standards.  Actual occupant behavior is not modeled, but rather an average is used based upon the number of bedrooms in the home.
    The rated home is assigned an index relative to the ‘reference’ home’s index of 100.  Each point above or below 100 represents a 1% increase or decrease in energy consumption (an index of 80 represents a 20% decrease, the minimum for Energy Star).    
    HERS ratings allow objective comparison between homes, financial evaluation of energy related improvements, and possible qualification for specific energy efficient building programs.  Potential uses of a HERS rating include:

• Energy Star for Homes program            (www.energystar.gov)
• LEED for Homes program                    (www.usgbc.org)
• Energy Efficient Mortgages                   (www.natresnet.org)
• Evaluating financial viability of improvements to existing homes
• Comparison shopping between homes