Solar window films consist of a low emissivity coating on a polyester substrate that is applied to the exterior of a flat glass, which makes the glass resistant to scratching. They also reflect heat. In places with extreme winters, this coating can be applied inside the window, thus reducing heat loss from the window.
Window films provide privacy. Choosing a tint of higher reflectivity obscures the outsiders’ view to things inside the house, and at the same time, it does not affect your view of the outside world. It also causes the glass to shatter less in case of an impact. Moreover, cooling makes up a huge chunk of your utility bill. Solar window films reflect up to 80% of the solar heat, thus reducing the room temperature. In short, it is a cheap and efficient alternative to reduce the room temperature and also the utility bills.
Dyed films are the cheapest alternative to tint the window. In such films, a dye is applied inside the window. These films are commonly used for automobile windows. It should be kept in mind that cheap dyes tend to fade over time.
Depositing films is a rather complex but inexpensive process. In this process, metals such as aluminum and nickel-chrome are heated in vacuum, under pressure and high temperature in the presence of argon. The gas gets heated and causes the metals to disperse particles onto the film, which is drawn into the vacuum tube. The layer coated onto the film has to be thick for this film to be effective.
The processing involved in applying sputtered films is the most expensive. A method similar to that used in depositing a film is applied: a vacuum chamber is employed, but metalization takes place at an atomic level. Electromagnetic field is used to bombard argon ions into the metals, which causes the metal atoms to get excited. These excited atoms get dislodged in small bursts and then get evenly distributed on the polyester film.
This is a far more effective film, as pigments or dyes are not used. Moreover, around 30 metals can be used, depending on what radiation you wish to subtract from the spectrum. The formed film is much thinner than the deposited film.
These films contain both the dye and reflective metal. This pairing improves the quality of the film. The mirror effect gets reduced drastically, while the color of the film is not compromised.
Others Types of Solar Window Films
- UV Films: UV films protect from about 99% UV radiation and are used mainly in shops. These films can also prevent the fading of items displayed near the windows facing direct sunlight
- Colored Window Films: These films are used to make the exteriors more attractive. Such films are usually used in windows of shops or for sporting the logo.
- Transparent Window Shades: As the name suggests, these are shades that are woven from PVC-coated polyester fabric and work pretty much like a film. They too come in a variety of colors and are transparent—hence, theses films do not block the view.