One of the things that is new to the window film industry in recent years is National Fenestration Rating Council (NFRC) ratings for window films. However, many people are still unsure of the importance of these ratings and what it means to them and their clients. This week, I will explain why this rating system is important to our industry and the data contained on these labels.

First, why does our industry need this rating system? Window films existed for decades without it, so why is it so important now? There are several reasons that this testing is important, but let’s start with the most obvious, credibility with both the building industry and consumers. For my first 10 years in the window film industry, there were no testing standards and the manufacturers were free to print whatever performance data they wished about their products. It goes without saying that some of this data was reported “optimistically” and the products never achieved the promised performance. This led many outside of our industry to view window films as a form of “snake oil” that did not live up to their promise. The industry’s reputation and product credibility suffered as a result, and many viewed window films as a product to avoid.

Also, testing methods often varied from one manufacturer to another. So, even if a manufacturer was reporting their testing data accurately, the differing methods made it very hard to compare products from different suppliers side by side based on the published data alone. Some manufacturers would report product performance information measured on single pane one eighth of an inch glass, while others used one fourth of an inch glass. There was no standardization in the testing and that could cause two very similar products to show noticeably different performance.

If window films were to be taken seriously and considered for things like Energy Star, federal rebate programs and other incentives, there needed to be some standards set and an assurance that the films would perform to the published values. Fortunately, an organization already existed in the National Fenestration Rating Council.

The NFRC was already doing standardized testing for the glass industry and their uniform testing was adopted to enable a consumer to compare the performance of competing window units with data they could rely on from an independent third party. Once window films began publishing NFRC performance data, they would have to abide by uniform NFRC testing rules and submit the performance data based on these standards.

Most major window film manufacturers have adopted this policy and test their films using the NFRC standards. For the first time, consumers can make an apples to apples comparison of several window films based on reported, standardized data. By beginning to use NFRC testing, the window film industry gained credibility that has led to rebates and incentives being offered by both utility companies and the government. You can identify films that are tested with NFRC standards by the label that will be affixed to outside of the box of film.
So, what does a NFRC label look like and what data is contained there? Let’s take a look:

As you can see in the diagram, there is a great deal of information and data listed. However, most people will focus in on their particular window type and compare the Solar Heat Gain Coefficient (SHGC) and Visible Transmittance (VT) data. These two pieces of data essentially tell you how well a product will block the heat and how much it will reduce the light passing through the window. The information is cross-referenced with the most common windows for both residential and commercial applications, so the consumer should be able to find a testing line that closely matches their circumstance. By comparing the SHGC and VT data of the various films they are considering, they will be able to make educated decisions about things like performance gain vs. cost or performance gain vs. drop in VT, etc.

I hope that this clears up what the NFRC label is used for, why it is important to our industry and why it is important to be educated about the data contained on these labels. Regardless of what is printed on the manufacturers marketing material, you can count on the data contained on the NFRC label to be an accurate and true representation of how one product compares to another. You can find out more about the NFRC and see that ratings on all tested window films by visiting their website at the link below.

http://www.nfrc.org/WindowRatings/index.html