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HERS Rating vs REScheck: Things to Know When Insulating Your New Home with Spray Foam

new home insulation | michigan insulation code | REScheck | hers rating

HERS Rating vs REScheck: Things to Know When Insulating Your New Home with Spray Foam Blog Feature
Eric Garcia

By: Eric Garcia on May 13th, 2020

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You’re about to start building your new house and you know you want spray foam insulation, but that means you’ll need either a HERS Rating or REScheck to meet building code insulation requirements.

So, what are these tests and how will they help you pass the insulation code? 

Don’t worry, as the Foam University Professor of Foam, I am going to explain both of these programs to you and how to get on the same page with your inspector.

When I’m not sporting the red jacket on Foam University, I am the general manager here at RetroFoam of Michigan and I work very closely with building inspectors. With that being said I can help you navigate through the confusion of passing insulation code through performance and how to prove it.

Now let’s get started.

Meeting Prescriptive Insulation Code with R-Value

There are certain thresholds, certain marks that you have to meet for prescriptive insulation code and ratings of the different types of insulation materials.

Looking at R-Value, code calls for that number to reach a certain point in different areas of the house, in various climate zones around the country.

Prescriptive code is all about meeting that certain R-Value and that’s it, which is great for fiberglass or cellulose, but performance is better suited for foam insulation as it takes into account R-Value, air permeability, and water solubility.

Performance Requirement to Meet Insulation Code

Performance requirements to meet insulation code can be a little trickier, and that’s where HERS Rating and REScheck come into play.

First, though, let me explain just a little what those performance requirements are to meet the insulation code.

Performance is more complicated than prescriptive because your insulation contractor has to prove how the spray foam works to the inspector. The contractor has to prove the insulation creates an air seal, that it has an aged R-Value, and several other variables.

Proving this is based on numbers and test results, from HERS Rating or REScheck, to show the insulation will perform in an efficient way and will also be safe in the home.

Let’s take a look at both of these programs and how they work.

What is HERS Rating?

A HERS Rating, or HERS Index, is a computer program that measures a home’s energy efficiency and calculating its energy performance.

HERS is the more popular program for checking performance at this time. There are even some homeowners who want the HERS Index Rating for their homes because it actually adds value when it comes time to sell.

This program tells the homeowner how efficiently their home is operating and where modifications can be made for better energy savings.

Only a person who is licensed can perform this test. This could be your contractor or a third party they bring in or recommend.

What is REScheck?

REScheck is a very common program used by contractors to prove the abilities of the insulation they have installed, as well as its efficiency.

In previous years, REScheck was the easiest program to use and the fastest because a contractor could enter their data and it would give them a pass or fail. It doesn’t give nearly as much detail as a HERS Rating, but it gives you the pass or fail information you need for your inspector.

Your contractor can likely perform this test for you.

HERS Index or REScheck for Your Home

Both of these programs are great for helping you show your inspector the performance of your home’s insulation. 

If you plan to use foam insulation, be prepared to have some lengthy conversations with your inspector. Unfortunately, it’s a fact that a lot of inspectors aren’t that familiar with foam insulation and how you can meet the performance code by using it.

They are absolute professionals, but it is something relatively new, so there may be a learning curve for both of you. These test results and your insulation contractor will be able to help you in relaying all of the pertinent information to the inspector.

You’re all in this together.

Related Articles

Spray Foam Insulation Code Requirements: How to Pass Code Without Meeting Prescriptive R-Value

Michigan Insulation Code: New Home Insulation Requirements

6 Tips to Get on the Same Page with Your Building Code Inspector During New Home Construction

Spray Foam Insulation for New Build Homes: Answers to Frequently Asked Questions


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About Eric Garcia

Eric brings his knowledge and training in building science, training in spray and injection foams from the manufacturers, more than 8 years installing foam insulation, as well as selling and managing in the foam insulation industry. He is also BPI and Dale Carnegie certified and has taken several building science courses including air sealing and building envelope. Eric’s responsibilities include overseeing and giving support to all of the branches of the RetroFoam of Michigan company, office, estimates, and installs. He is also the Professor of Foam on our educational YouTube series Foam University. Even when Eric is off he is usually still “working” or thinking about work, but when he can get away he enjoys camping, hiking, hunting, and woodwork.