Definition of Technical Terms for Window Films

An interior film that has a silver reflective surface on the outside and a neutral surface on the inside. It is commonly referred to as "one-way reflective film," although it also comes in lighter shades that don't offer as much privacy.

A film that gets its color and appearance by adding a dye to the film surface or adhesive. This is often done with automotive films.

In the Deep Dyed films colors are embedded in the film rather than color coated on the outside of lower-priced films. Discoloration and scratching can be avoided in Deep Dyed window films since it is covered with translucent adhesive using color polyester film. It displays enhanced appearance and efficiency.

A film that uses both metallized film and dyed film processes to achieve its color and appearance. See also Dyed Film and Metallized Film.

A film that obtains its color and appearance by adding a metal layer to the film surface, either by a sputtering or a deposition process. This is often used for flat glass films as well as high performance films for the automotive industry.

Also known as "Frost Film", these films provide excellent privacy protection with a sandblasting effect.

This film, also known as "neutral film," generally has a non-reflective appearance. However, it still contains metallic components.

Sputtering - cathode sputtering, is an innovative technology used in the production of window films. These provide excellent insulation while maintaining excellent optical clarity. During sputtering, different layers of various metals, such as silver or titanium, can be introduced into the polyester film. By selecting specific metals, it is possible to selectively target specific wavelengths of the sunlight spectrum.

The most common unit of measurement for the window film thickness, where 1 MIL is equal to 1/1000 of an inch (.001″), or 25.4 µm (microns)

is the ratio of visible solar energy that passes through a glazing system to the total visible energy falling on the system. Higher the VLT more is the light inside the room.

Visible light reflectance is the amount of light reflected away by the film. This is commonly separated into interior and exterior ratings because some films have two different sides. While having a high reflectance means less light is coming in the room, many people do not want to cause too much glare. If this is the case, shoot for a medium film with a rating of about 25-30%.

is the measurement of the percentage of solar radiation that passes directly through a glazing system.

is the measurement of the percentage of solar radiation reflected by the glazing system.

measurements express the percentage of solar radiation absorbed by the glazing system.

is the measurement of the percentage of solar radiation in the ultra-violet region that passes directly through the glazing system.

Solar Energy: Consists of 4% – UV Rays (0-380nm), 43% – Visible Light (380nm-780nm) and 53% – Infrared Rays (780nm-2500nm, main source of heat)

is the sum of energy transmitted, reflected and absorbed by the system. It represents 100% of the solar energy.

is an important measure of the ability of a glazing system to reject solar heat in the form of visible light and infrared radiation. This is made up of the proportion of solar energy rejected and the proportion of solar energy absorbed and re-radiated to the outside. It is the performance value of the heat rejection - its counterpart is the SGHC value.

is the overall heat transfer co-efficient of the glazing system. It is the amount of conductive heat energy (BTUs) transferred through one square foot of the glazing system during one hour time period for each one degree Fahrenheit temperature difference between indoor and outdoor air. Lower the U-factor, better is the insulating quality of the material.

is the ratio of solar heat gain through a given glazing system to that of a clear float glass of 1/8 inch (approx. 3mm) thickness under the same test conditions. Lower the shading co-efficient, better is the ability to reduce solar heat. Emissivity measures the surface ability to absorb or reflect Far Infrared Radiation. Lower the emissivity rating, better the insulating quality of the material. Glare Reduction is a measurement of the reduction in visible light transmission after applying the film to the system as compared to the visible light transmission earlier. (It is represented in%). Solar Heat Gain is the sum of percentage of solar energy that is either transmitted or absorbed and then re-radiated into the room.

The emissivity is the measure of the ability of a surface to absorb or reflect far-infrared radiation. The lower the emissivity, the better the insulating capacity of the material.

Glare reduction is a measure of the reduction in visible light transmission after the film is applied to the system compared to the previous visible light transmission. (It is expressed in %).

is the second important parameter, as a counterpart to the TSER value, which describes the actual heat transmission of a glazing unit. This is composed of the solar energy that passes directly through the window (transmittance) and the proportion of solar energy absorbed and re-radiated to the inside. It is the performance value of heat gain - its counterpart is the TSER value.

A measure of the rejection or shielding of the portion of infrared radiation in solar energy, usually specifying a particular range of the IR spectrum that lies between 780 and 2500 nm