How to Shop for Window Film
Window film choices can be baffling, with a wide array of brands and performance options available. This page will give you a few tips on sorting through the hype and the variety, so you can make a more informed decision.
One size does not fit all.
Or more precisely, a particular film is probably not the best choice for every situation, or even for every window in the same house or commercial building.
For starters, sun control needs vary with direction. East and west-facing windows have by far the greatest heat gain and may require a more aggressive sun control film. South facing windows, on the other hand, are exposed to sunlight during the winter months when heat gain is desirable. For south-facing windows, protection against glare and the ultraviolet (UV) light that fades fabrics and furnishings is important, but letting heat in is actually a good idea. Glare reduction is usually the primary concern for north-facing windows.
And there are big differences in safety and security films. Is the primary goal to slow down and deter intruders, or to prevent shattered window glass from becoming deadly in the event of an impact or a bomb blast?
An Engineered Group window film professional can answer your questions and help you arrive at the best solution for your specific needs.
Don’t be baffled by buzzwords.
The two biggest buzzwords in window film today are nanotechnology and ceramic. And in the interest of full disclosure, 3M uses these terms in its marketing. Let’s take a look at what each of these terms really mean within the context of window film.
Ceramic. Window films marketed as “ceramic” offer high visible light transmission and clarity, but claims that these films have no metal are just not true. The material that provides the primary sun control mechanism in such films is titanium nitride. While it is true that titanium nitrade behaves in some respects like a ceramic material, it is still, nevertheless, a metal.
Nanotechnology. This term refers to the thickness of materials formed, deposited or otherwise manipulated at very small scales—in some cases at a molecular or even at an atomic level. A nanometer is one billionth of a meter, or 0.0000000394 inches.
However, the use of nano-scale materials in window films is not new. The very first window film patent in 1966 (issued to 3M) described a process for depositing metal on a polyester film at metal thicknesses equating to about 3 to 13 nanometers.1
By comparison, the titanium nitride in various “nanotechnology ceramic window films” is applied at thicknesses of between about 10 and 100 nanometers.2
So if we’re going to be throwing around buzzwords like nanotechnology and ceramic, then it is factually accurate to say that 3M research scientists invented the world’s first nanotechnology window film in 1966!
“Clear” doesn’t mean what you think it does.
Just as a yellow pages ad for a plumber offering 24-hour service does not mean the gentleman is willing to show up at your house to fix a clogged sink at three in the morning, a “clear” window film—or window glass—does not transmit 100 percent of the visible light that passes through a window. Or even 80 percent.
Standard single pane window glass transmits about 75 percent of the visible sunlight that strikes the glass. And a window film is considered clear if it transmits about 60 percent of the sunlight that strikes it. For the average person, 60 to 70 percent visible sunlight transmission is perceived as 100 percent.
Higher visible sunlight transmission is generally perceived as glare. Also keep in mind that 44 percent of the energy in sunlight comes from the visible wavelengths.
What clear really means, with respect to window film, is that the film does not have any visible “tint” as a result of color dyes or reflective metal particles.
The number of window film brands isn’t what it seems.
The number of window film brands advertised today suggests that customers can choose from among a couple dozen manufacturers. Some window film dealers tout a broad selection of window film brands as an indication that customers can somehow obtain a better price or otherwise better meet their needs based upon variety.
More often than not, the appearance of brand variety is an illusion.
The reality is that the window film industry has experienced substantial consolidation during the past few years, with the end result that only four major manufacturers and perhaps a handful of smaller independents exist today. The four major manufacturers are 3M, Eastman Chemical Company, Lintec and Saint Gobain. And we’re guessing you may only recognize one of those four names. 3M.
In fact, of all the window film brands owned by the four major manufacturers listed above, 3M™ Window Film is the only brand continuously manufactured and sold by the same parent company throughout its history. And 3M has no secondary window film brands. 3M™ brand window films are the only window films sold by 3M.
In sharp contrast, EnerLogic®, FormulaOne®, Gila®, Huper Optik®, IQue™, LLumar®, Nanolux™, Sun-X™, Vista™ and V-KOOL® window films are all manufactured by the same company: Solutia, Inc. Yes, really. A spinoff of the Monsanto Company, Solutia pursued a very aggressive strategy of acquiring smaller window film manufacturers to build up market share, but then was itself acquired by the Eastman Chemical Company, just four years after going through a Chapter 11 bankruptcy.3
The Solar-Gard® window film brand is owned by Saint-Gobain, a French multi-national building products company. The Madico and Solamatrix® window film brands are owned by Lintec, a Japanese printing technology company.
- U.S. Patent 3,290,203 to David L. Antonson and Gerald A. Berger of Minnesota Mining and Manufacturing Company (3M’s original name) on December 6, 1966, disclosed vapor coating a “highly metallic reflective layer on the order of 25–125 angstroms thick” on a polymer film.
1 angstrom = 0.1 nanometers, so 25–125 angstroms is 2.5–12.5 nanometers.
- The first patent for a window film employing titanium nitride does not state the preferred thickness for the titanium nitride layers, but reported data relating nitrogen flow during the sputtering process to the electrical resistance of the finished metalized polymer sheets suggests titanium nitride layer thicknesses of 10-30 nanometers. See Fig. 9, U.S. Patent No. 6,188,512 to Woodard, et al. (2001). A second patent issued to the same inventors a few years later suggested that titanium nitride experienced a tendency to crack when deposited directly on a flexible polymer sheet. See U.S. Patent No. 6,707,610 to Woodard, et al. (2004).
- Based in Saint Louis, Missouri, Solutia filed for Chapter 11 bankruptcy protection on December 17, 2003 and emerged from bankruptcy on February 28, 2008, which, unfortunately, precisely coincided with the severe economic downturn triggered by the subprime mortgage crisis. Solutia was acquired by Eastman Chemical Company of Kingsport, Tennessee in July 2012.