HERS

What is a HERS Rating? A home energy rating involves an analysis of a home’s construction plans and onsite inspections. Based on the home’s plans, the Home Energy Rater uses an energy efficiency software package to perform an energy analysis of the home’s design. This analysis yields a projected, pre-construction HERS Index. Upon completion of the plan review, the rater will work with the builder to identify the energy efficiency improvements 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 inputs derived from the plan review, are used to generate the HERS Index score for the home.

 

entry continues below ↓

The HERS Index

The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home’s HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.

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 HERS Reference Home and a home with a HERS Index of 80 is 20% more energy efficient.

For more information, visit the RESNET Web site.

Comparing the New HERS Index with the Old HERS Score

For homes rated before July 1, 2006, the rating score is known as a “HERS Score.” The HERS Score is a system in which a home built to the specifications of the HERS Reference Home (based on the 1993 Model Energy Code) has a HERS Score of 80. Unlike the HERS Index, each 1-point increase in a HERS Score is equivalent to a 5% increase in energy efficiency. Please see below for a comparison of the HERS Score and the HERS Index.

 

HERS Score (Phasing out)   

• Reference Home is assigned a HERS Score of 80   
• Reference Home Basis - 1993 Model Energy Code (MEC)    
• Scale - Each 5% increase in energy efficiency corresponds to a 1-point increase in HERS Score    
• Energy Use Considered - Heating, cooling, and water heating    
• ENERGY STAR Requirement - HERS Score 86    
• Status - Phasing out  
  

HERS Index (Approved by RESNET)

• Reference Home is assigned a HERS Index of 100, while a net zero energy home is assigned a HERS Index of 0
• Reference Home Basis - 2006 International Energy Conservation Code (IECC)
• Scale - Each 1% increase in energy efficiency corresponds to a 1-point decrease in HERS Index
• Energy Use Considered - Heating, cooling, water heating, lighting, appliances, and onsite power generation*
• ENERGY STAR Requirement - HERS Index of 85 in climate zones 1–5 & HERS Index of 80 in climate zones 6–8
• Status - Approved by the RESNET Board of Directors. Implemented July 1, 2006.
  

* Note that although onsite power generation is included in the RESNET HERS Index, it cannot be used to decrease a HERS Index to qualify for ENERGY STAR.

 

HHI Error Correction Policy

HHI is committed to accuracy of content and correcting information that is incomplete or inaccurate. With our broad scope of coverage of healthful indoor environments, and desire to rapidly publish info to benefit the community, mistakes are inevitable. HHI has established an error correction policy to welcome corrections or enhancements to our information. Please help us improve the quality of our content by contacting allen@healthyhouseinstitute.com with corrections or suggestions for improvement. Each contact will receive a respectful reply.

Ads, ad links, products and content on this page are not necessarily endorsed by these organizations.