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What is a HERS rating? Follow

A home energy rating, or HERS rating, is an analysis of a home's projected energy efficiency compared to the efficiency of a 'reference home' that meets the requirements of the latest residential energy code, known as the International Energy Conservation Code (IECC). A home energy rating involves both an analysis of a home’s construction plans, as well as onsite inspections and testing by a certified Home Energy Rater. A Home Energy Rater uses specially-designed software to analyze the expected energy use of the home based on the home’s construction plans. This analysis yields a projected, pre-construction rating score for this home (called a HERS Index). When the rating is being conducted for the purposes of ENERGY STAR certification, the Rater then works with the builder to identify the energy efficiency features needed to ensure the house will meet ENERGY STAR performance guidelines.

The Rater then conducts onsite inspections, typically including a blower door test (to test the leakiness of the house) and a duct test (to test the leakiness of the ducts). Results of these tests, along with data from the software analysis, are used to generate a final HERS Index score for the home. The lower a home’s HERS Index, the more energy efficient it is. A home built to code scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus, a home with a HERS Index of 85 is 15% more energy efficient than the reference home and a home with a HERS Index of 80 is 20% more energy efficient. Learn more about the ENERGY STAR Partnership for Home Energy Raters. The HERS rating system is administered by RESNET -- the Residential Energy Services Network.



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