Why all HERS®/ERI Index Scores are Increasing Nationwide

It is important to understand the Home Energy Rating System (HERS®) and Energy Rating Index (ERI) are describing the same thing. HERS is a proprietary acronym created by the Residential Energy Services Network (RESNET), so the term ERI has been used for the code language. RESNET is the governing and standard setting body of the home energy rating world. RESNET recently created the ANSI/RESNET/ICC 301-2014 standard that describes how the Index score is developed. Within the 2015 IECC language that used to describe how to develop an ERI score has been replaced in the 2018 IECC with the ANSI 301 standard. In addition, the standard has now been incorporated into every software used to develop a HERS® or ERI Index score.

The ANSI standard change has, and will, cause all HERS/or ERI index scores to increase across the country. Due to this score increase and other fixed mandatory requirements in the ERI pathway, it is unlikely that jurisdictions will see builders using the ERI path for quite some time.

For more information on why this is happening, please refer to the following article: HERS® Energy Rating Index Scores are Going Up!

Software developers have incorporated the new ANSI/RESNET/ICC 301-2014 standard into their systems. As stated before, they are all consistently seeing the HERS/ERI index scores increase. Currently, there are three software systems available:




EnergyLogic is in the process of transitioning to the Ekotrope compliance software which will change the look of the reports but will not affect the content of the reports. Click here to see a sample Ekotrope report. All three software versions have incorporated reference homes to developed code compliance documents for the UA Tradeoff, Simulated Performance, and Energy Rating Index pathways through the energy codes.

What is a reference home?

Imagine your two hands are two homes that are geometric twins of each other. Your left hand, the reference home, is a house built with the energy and aesthetic features defined by the code which uses a quantifiable amount of energy that the code has deemed to be the minimum amount allowed by the jurisdiction.  Your right hand is the home you want to build, the proposed design, with the energy and aesthetic features you believe, are best to achieve whatever goal you have for the home: cost- effectiveness, safety, aesthetic beauty, comfort, durability, efficiency or livability. Your home, the proposed design, on the right, is compared to the code reference home on the left and if your home’s performance is equal to or better than the reference home it complies with the code and can be permitted to be built. The jurisdiction, an approved third-party, or both will inspect, verify, and report that the home was built as proposed in order for the certificate of occupancy to be released. 

For more detailed information, please refer to the following article: Simple Explanation of the IECC

In summary, changes and upgrades to software systems are inevitable. The creation of the ANSI/RESNET/ICC 301-2014 standard was the most impactful, but every version upgrade affects something. As a result, RESNET has developed a standard that governs when Energy Raters must transition to the most recent version of a software.

For more information on this subject, please refer to the following article: Important RESNET® Amendment on Rating Software Changes (Persistence)


Robby Schwarz (faked)

Who to Contact:

Robby Schwarz
Principal, Director of Builder Relations

Email Robby

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