The Home Energy Rating System (HERS) Rating Process

In addition to the general HERS rating information on this page, see specific information for new homes, existing homes, and commercial ratings and Stretch Energy Code and the 2012 IECC code compliance.

An HERS energy rating includes following:

  • Blower door testing for building air leakage
  • Heating and cooling duct testing for air leakage
  • Overall assessment of home energy requirements
  • Assessment of areas of potential energy reduction improvements
  • Rating of home energy requirements compared to energy code and other houses
  • Certification of houses and house plans to meet Energy Star requirements
  • Certification of houses to meet Stretch Energy Code

An Overview of the Energy Rating Process

  • The Checklist - The energy rater completes a checklist that includes:
    • Basic house facts: style, age, square footage, number of bedrooms, measurements of walls and ceilings, type of floor or basement, etc.
    • Construction details: types of walls and foundation, condition of the ceiling, roof, attic and basement; method and adequacy of ventilation, blower door test results, etc.
    • Drawings & photos: building footprints; sketches and measurements of building components; and photos of all sides of the house, heating and hot water systems, a typical window, an interior basement wall, unfinished spaces, and any unusual conditions.
    • Windows & skylights: style, size, number, how many layers of glass, orientation, features, etc.
    • Insulation: type, thickness and total area in the walls, ceilings, foundation, floors and slab edges (typically determined by visual inspection and the use of a probe in building openings).
    • Space and hot-water heating systems: manufacturers, ages, model numbers, type of fuel, where sited, number of heating zones, and any special features (insulation blankets, dampers, setback thermostats, etc.)
    • Utility information: names of electric utility and oil and/or gas dealers; availability of natural gas; type of fuel for range and clothes dryer; cords of wood, if used; and owner's authorization, if available, for the release of billing records.
  • The Analysis - A computer program analyzes the data and assigns points for each item. The HERS rating system is a "performance-based" system with flexibility in meeting energy standards. All information is taken into account. No single feature or building technique is required. The total number of points determines the rating.
  • The HERS Rating and Energy Improvements
    • Current Energy Costs: the program computes the average monthly energy costs the occupants will pay taking into account the specific electric utility and fuels used.
    • Potential Energy Savings: If a home is rated above the 100 points of the HERS Reference Home, the homeowner is provided with a list of the most cost-effective improvements with estimated costs of materials and labor needed to bring the home down to 100 points (rating an "up to code" new home), and projected energy savings after improvements are made.
  • The Report - The Energy Rating sheet, Star certificate, and the supporting documentation are mailed to the person who ordered the rating. Copies sent to the other parties (lender, builder, buyer, seller, Realtor, etc.).

A HERS score of 70 or below on this report will be used to meet the Stretch Code requirement for houses of 3000 square feet or less. For houses greater than 3000 square feet a HERS score of 65 or below will be required.