One of the new things in 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 the NFRC ratings and what it means to them. In this post, I want to explain the importance of this rating system and then explain what information you will find on the labels now coming with most major window film manufacturers’ products.
First, why does our industry need this rating system? We existed for decades without it, so why is it so important now? There are several reasons that I feel this testing is important, but let me start with the most obvious, credibility with both the building industry and consumers. For my first ten years in the window film industry, there were no testing standards, and the manufacturers could 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 in the building industry to view window films as “snake oil,” and our industry’s reputation suffered as a result. That view of film products was often passed along to consumers, and window films were viewed by many as a product to avoid.
Second, even when manufacturers were doing legitimate testing and reporting the results correctly, often the testing methods varied from one manufacturer to another. This made it very hard to compare products from different suppliers side by side based on the published data alone. Some would report their product’s performance on single pane 1/8” glass, while others used 1/4” glass. There was no standardization, and that led to a variety of results even when the testing was reported accurately.
For window films to be taken seriously and be 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 at the published values. Fortunately, an organization already existed in the NFRC that was doing testing of this type for the glass industry. 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 (The NFRC). Once window films were included in the NFRC, manufacturers 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 tested their films using NFRC standardization. This truly allows people to make an apples-to-apples comparison of several window films based on reported, standardized data. By using NFRC testing, the window film industry has gained credibility, and the rebates and incentives being offered for installing window films are getting better every year.
So, what does an 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 on their particular window type and compare the Solar Heat Gain Coefficient (SHGC) and Visible Transmittance (VT) data. The most common windows for both residential and non-residential uses are listed, so the consumer should be able to find a testing line that closely matches their application. By comparing the SHGC and VT data of the various films they are considering, they can make educated decisions about things like performance gain vs. cost or performance gain vs. drop in VT, etc.
I hope that this clears up exactly what the NFRC label is used for and why it is important to understand the data contained on these labels. Regardless of what is printed on the manufacturer’s marketing material, you can count on the data contained on the NFRC label to be accurate and a true representation of how one product compares to another. You can find out more about the NFRC and see the ratings on all tested window films by visiting their website at the link below.