The Ultimate HERS Rating Guide Part 1: What Is A HERS Rating?

Date Published: December 8, 2015

The HERS Rating Index, developed by RESNET:

More new homes are being built with a HERS Rating, particularly in Colorado.  The Home Energy Rating System (HERS) is a method used by architects, builders, and energy raters, to determine the overall energy use of a home.

RESNET, the Residential Energy Services Network, developed the HERS Index standard, which is a nationally recognized standard for measuring the energy efficiency of a home.  Many Colorado home builders use the HERS score to rate their homes, and several area municipalities use the HERS score to validate whether a home meets their energy codes, including the City and County of Boulder.

What does a HERS Rating say about a home?

The HERS rating measures a home’s energy efficiency and can tell you how efficiently it is operating and where you can make modifications for greater energy savings.  When you are selling a home, a low HERS Index Score can command a higher resale price.  And when buying a home you can anticipate the costs of energy bills and efficiency upgrades.

The video included in this post was published by RESNET to give an overview of the HERS Rating process. In the video, they mention a very important point about the HERS score. If a home has a lower HERS score, meaning it is more energy efficient, the price of the home should increase in value.

People want to buy more energy efficient homes. It reduces their monthly expenses, reduces their carbon footprint, and helps when they need to sell later. This shift has been reflected in many facets of the home buying industry. Just recently, the HERS score was added to many of the MLS providers so buyers can see a home’s efficiency when looking at the listing.

So what does a HERS Rating say about a home? A lot really. And because of that, it is becoming more and more popular among builders, building departments, and the general public.

Are you a Colorado Builder in need of a HERS Rating for your next building project? Learn more about our certified HERS Rating Services here. 

How does the HERS Index work?

To calculate the HERS Score, the rater performs a full energy rating on the home by analyzing information on the home’s energy aspects using a sophisticated software modeling tool. The results of the data analysis are compared against a “reference home” which is the same size and shape as the actual home, and from which a resulting HERS score is created.  The lower the score, the better. A lower score means the home is more comfortable and energy-efficient.

For example, a home with a HERS Index score of 70 is 30% more efficient than a standard new home, while a home with a score of 130 is 30% less efficient than a standard new home.  A HERS Index score of Zero would mean the home consumes net-zero energy and likely has renewable energy installed on the home, such as Photovoltaic (PV) Solar panels.

Field testing and verification is performed on all HERS ratings, including verification of insulation levels, window specifications, heating, cooling, water heating specifications, appliance and lighting specifications, in addition to performing blower door air leakage testing.

We will go into even deeper detail of the HERS score index in part 2.

What Is A HERS Rating: Image of Insulation Inspection verifying it meets plans.

What does it take to complete a HERS rating?

Obtaining a HERS rating is a multi-step process. There are steps to take before, during and after the construction process, but the 3 main stages are as follows.

Projected HERS Rating: Typically, before ground is broken on a new construction project, a projected HERS must be completed. This is where a certified HERS rater takes the plans for the project and uses them to project what the HERS rating will be if the plans are followed exactly.

Mid-Construction Verifications: During construction, the HERS rater will need to verify that the builder is following the plans and that the rating is on track to meet the projected rating. Some of these items cannot be seen or altered when construction is complete. Because of this the rater will go to the site and check these items. This includes insulation levels and duct leakage ratings.

Final HERS: The final HERS inspection occurs just as construction is coming to an end. At this point, the rater will go out to the site, verify that everything that was projected was installed, complete the final tests like blower door testing, and collect the final data for the rating. This completes the HERS Rating process.

Certified HERS Raters on staff:

If your new construction or remodel/addition project in Colorado requires a HERS Rating, or you simply want to understand the energy performance of your home, contact Scott Home Inspection.

We have Certified HERS Raters on-staff who can help with your project.  We have completed hundreds of HERS Ratings on homes throughout Colorado, and have extensive experience in the City and County of Boulder, meeting the city of Boulder’s Energy Conservation Code and Boulder County’s BuildSmart program requirements.

For more information visit the Energy-Service page of our website.

Also for more information about RESNET and the HERS Rating Index, visit the RESNET website.

HERS Rating - Scott Home Inspection

Also, keep an eye out for our follow up blogs, that will dive even further into the HERS process.

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About the Author: George Scott

George founded Scott Home Inspection in 2006, and has grown the business into a multi-inspector firm serving the Colorado Front Range, from Fort Collins down to Colorado Springs. As an ASHI Certified Home Inspector and Certified Energy Rater, George is an excellent resource to help with inspection and energy-related requirements.

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