The HERS or Home Energy Rating System is an established measurement of a home's energy efficiency. As a home buyer, you can easily compare the energy cost of the home being considered by using the Home Energy Rating.
A Home Energy Rating evaluates and measures your home's energy characteristics. The following are just a few items that a home energy rating will consider: the construction & materials of the home, insulation levels, window/door types & efficiency, the window/door to wall area ratios, appliances and lighting (including the water heater), mechanical system (heating and cooling), the orientation of the house, the size of the conditioned area in square feet, and the leakage or air infiltration of the building (house) envelope and duct work.
The Home Energy Rating is completed from on-site visits using test equipment like the blower door and duct tester and from blueprints on new homes. With information now gathered by the rater, data is electronically calculated using Nationally Approved Software and converted to the HERS Index. The lower the index score, the more efficient your home will be. The following chart is a representation of the HERS Index.
- The Index score for the average home. This home was built before the 2006 IECC (International Energy Conservation Code).
- The Index score for the home built to the 2006 IECC (International Energy Conservation Code).
- The home is built to the Energy Star Stanard, which is typically 15% more efficient than the 2006 IECC built home.
- Net Zero Energy Home produces as much (or more) energy than it consumes (from the grid) by Solar, Wind or other power generation means.
RESNET Ratings provides a relative energy use index called the HERS Index - a HERS Index of 100 represents the energy use of the "American Standard Building" and an Index of 0 (zero) indicates that the Proposed Building uses no net purchased energy (a Zero Energy Building). A set of rater recommendations for cost-effective improvements that can be achieved by the Rated Building is also produced.
RESNET standards encompass three areas:
- Software accreditation achieved by passing a battery of software verification tests developed by U.S. National Laboratories and RESNET.
- Definition of knowledge base and skill sets that a rater must demonstrate through passing an online RESNET National Rater Test.
- A quality assurance evaluation that features each Rating Provider employing a certified Quality Assurance Designee. The Quality Assurance Designee must annually independently verify internal consistency of a minimum 10% of all building input files and independently field verify the accuracy of a minimum of 1% of each certified Rater’s homes.