Do Low-E and Tinted Windows Affect WiFi or Other Radio Frequency Energy?

December 08, 2021

Do my windows affect radio frequencies (RF) such as wireless Internet signals and mobile phone service? The answer to this question is a hearty "it depends." While there are numerous physical barriers that may weaken RF signals such as Wi-Fi (i.e., cabinets, kitchen appliances, Bluetooth devices, concrete, masonry, etc.), one assumption that many people incorrectly make is that factory-tinted windows can have a detrimental effect on the strength of such signals too.

With factory-tinted windows, only the color of the glass is altered — and not any high performance or metalized coatings. Low-E coatings on the other hand may impact RF energy. But in most cases, if you want to safeguard a facility from electronic theft and maintain privacy from the outside world, using a purpose-built solution is necessary to ensure the best levels of protection.

In this post, we'll discuss the function windows serve, the difference between Low-E glass and RF-attenuating window films, and why factory-tinted windows don't get the job done and more. Here's a closer look:

The Purpose of Windows
While these may be stating the obvious, let us highlight the primary purposes of windows in a structure:
• Windows provide natural daylight to residential, commercial, and industrial facilities.
• Windows are key as it pertains to aesthetics.
• Natural daylight has been proven to improve human comfort and health.
• They can help maintain indoor comfort (i.e., keeping heat outside during the summer and keeping the cold outside during the winter).
• They help with noise reduction.
• They complement a facility's overall security.

Low-E Glass Explained
So just what is Low-E glass? Low-E stands for "low emissivity." Specifically, this is a type of thin metallic coating that helps reduce heat gain or heat loss by working to reflect infrared and radiant heat that comes into contact with the glass. In use for decades now, these come in a variety for forms from every major glass manufacturer. Essentially, Low-E helps minimize solar heat gain and improve energy efficiency.

Window Coatings and RF
Because of what Low-E coatings do for radiant heat, there may be some potential impact to RF signals. Factory-tinted color conversely, has very little effect on RF in most cases, unless the color is achieved through metallic coatings rather than dyes. However, even Low-E coatings aren't usually significant enough to severely impact a cell or Wi-Fi signal to the point of preventing usability. Know that RF transmission is contingent on many materials and many factors, not just windows. While windows are typically the "hole-in-the-bucket" of sorts for RF, RF will often find its next best path into or out of a building — whether this is the walls, roof, or something else. It’s extremely difficult to completely stop or prohibit all RF from entering or exiting a building without going to more extreme measures. However, it can be mitigated.

RF Window Films
If you’re trying to intentionally reduce RF transmission through glass, consider purpose-built solutions such as RF films. And, while it's true that Low-E coatings may provide some reduction of certain radio frequencies, this isn't what they're designed to do. RF window films on the other hand, are purpose-built for such a role. And if you combine them together, that is installing RF films on top of Low-E glass, it can potentially offer even more protection.