What is the RESNET HERS Index?

RESNET HERS Index chartRESNET uses the Home Energy Rating System (HERS) to rate a home's energy efficiency. The HERS Index illustrates a range of numbers, or scores, that can be used to compare the energy use of two homes.

The HERS Score is a number that represents the relative energy use of a rated home as compared with the energy use of a home built to today's minimum building code. The HERS system allows for an apples-to-apples energy efficiency comparison of different houses.

A HERS Index of 100 represents the energy use of the standard home

A HERS Index of 0 represents a home that uses no net purchased energy

A HERS Rater provides recommendations for cost-effective improvements that can reduce energy use in a home (and therefore lower the HERS score).

How is the HERS Index Calculated?

Computer software, such as REM/Rate, is used to analyze the results of an in-depth assessment of an existing home or the components of a new home design. The assessment includes analysis and inspection of:

windows, doors, insulation, and ducts to find and measure leaks

all heating and cooling equipment to ensure occupant health and safety

Specialized diagnostic equipment, such as a blower door and duct blaster, help to provide detailed measurements of the energy efficiency issues. In addition to yielding an energy rating, the report will provide a cost benefit/analysis, with expected return on investment for suggested repairs and upgrades. This makes it easier for the homeowner to prioritize recommended treatments.

How is the Number Used?

RESNET has grown in popularity as a result of its far-reaching impacts. Here are several examples of groups that use the HERS score:

STATES use home energy ratings in establishing minimum building code compliance.

HOMEOWNERS use scores to estimate the cost of maintaining a particular home and evaluate the cost-effectiveness of options that can improve energy efficiency.

BUILDERS modify home designs based on rating guidelines to meet buyer demand for maximum comfort at a minimal cost.

MORTGAGE COMPANIES recognize ratings as a tool and require them to qualify loan applicants for certain federally sponsored mortgage products.

The HERS Index is also one of the metrics used to qualify a home for an EPA ENERGY STAR certification label.

Become a HERS Rater Now

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