There are many types of window tint available in the market for a wide variety of uses from solar heat reduction to UV protection, privacy to safety and security, decorative applications to heat retention.
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Heat rejection films are normally applied to the interior of flat glass windows to reduce the amount of infrared, visible light, and ultraviolet (UV) radiation entering windows. Such films are either dyed or metalized (which can be transparent to visible light) to convert incoming solar radiation to infrared radiation, which is then rejected back through the glass to the exterior. Modern window film technology has created Ceramic Window Film which are non-metallic and do not contain dyes that can result in discoloration. The dyed and metallic window films usually cost 10-15 percent more than regular windows but can reduce energy loss by as much as 30-50 percent."[1] Ceramic window films cost slightly more but provide a substantial increase in blocking UV rays and ability to control heat transfer.
To keep the sun's heat out of the house, a low-emissivity coating should be applied to the outside pane of glazed windows. If the windows are designed to provide heat energy in the winter and keep heat inside the house (typical of cold climates), the low-emissivity coating should be applied to the inside pane of glazed windows. Such films also reduce the amount of visible and ultraviolet radiation entering a window, and are often applied to reduce fading of the contents of a room. Silvered film may also be employed to the same end. Spectrally selective films act by blocking certain wavelengths of the sun's infrared radiation and reject heat without reducing natural light.
Security films are applied to prevent glass from shattering. Typically applied to commercial glass, these films are made of heavy-gauge plastic and are intended to maintain the integrity of glass when subject to heavy impact. The most robust security films are capable of preventing fragmentation and the production of hazardous glass shards from forces such as bomb blasts. Some companies have even experimented with bullet ballistics of multiple layers of security film.[2] Another key application for security window films (safety window films)is on large areas of "flat glass" such as storefront windows, sliding glass doors, and larger windows that are prone to hurricane damage. These security films, if applied properly, can also provide protection for vehicles.[3] These security films are often tinted and can be up to 400 micrometers (µm) thick, compared to less than 50 µm for ordinary tint films. If anchored correctly, they can also provide protection for architectural glazing in the event of an explosion.[3] A layer of film (of 100 µm thickness or greater) can prevent the ejection of spall when a projectile impacts on its surface, creating small dagger-like shards of glass that can cause injury.
Switchable films can be switched from opaque to clear by a safe voltage under 36V AC. In its opaque state, it can be perfectly used as a projection screen that is viewable from both sides. 3G switchable film also has UV (100%) and IR (94%) blocking functions and security function.
Graphic design films are generally colored vinyl or frosted. Frosted finish films closely resemble sandblasted or acid-etched glass, while vinyl films are available in a range of colors. Both types of films are commonly used in commercial applications.
Privacy films reduce visibility through the glass. Privacy film for flat-glass commercial and residential applications may be silvered, offering an unimpeded view from the low-light side but virtually no view from the high-light side. It may also be frosted, rendering the window translucent but not transparent. Privacy films for automobiles are available in gradients of darkness, with the darker tints commonly known as "limo tint."
Correctly-applied mirror film can create one-way mirrors.
Other benefits include protection for passengers in the rear, protection from UV rays (which have some harmful effects), cooling for pets, greater privacy, reduced chance of theft (because valuables are less visible), reduced glare and reflection on liquid crystal display (LCD) screens, and protection for those who have conditions involving photosensitivity or skin sensitivity, such as lupus (SLE). Window film is also considered more effective and practical than stick-on blinds.
Not all films are suitable for all glass. You must consider the absorptance of the glass and the film, the size of the pane, the thickness of the glass, the construction of the window – is it single pane, insulated glass, treated (with a low-emissivity coating), laminated or toughened.
Advice on the appropriate selection of film for the glass is vital to ensure that the glass does not crack as a result of thermal stress. However, it is possible that a pane of glass may break subsequent to the application of an appropriate film, because the pane has been damaged during the glazing of the window, or as a result of movement of the building or other physical stresses that are not apparent at the time of the application of the film.
Glass may crack subsequent to the application of signwriting or if heavy, thermally efficient drapes are hung close to the glass, particularly if the edges of the glass are damaged.
The chances of glass breakage occurring subsequent to the application of film or signwriting or the hanging of drapes, are very small. However breakage can occur and it is impossible to predict the edge condition of the glass without removing it from the frame – an approach that is not practical.!
Under certain conditions, window film will exhibit iridescence. This phenomenon usually occurs at night, when the source of illumination within a building is fluorescent lighting.
The amount of iridescence may vary from almost imperceptible to very visible. It most frequently occurs when the film is constructed with scratch resistance protection.
When iridescence does occur in window film, the best way to stop it is to prevent the fluorescent light from illuminating the film or to use an alternative type of light.
The thicker window films known as safety and security window film are designed to perform under extreme conditions, and as such there are specific standard criteria these films should meet, such as American standards ANSI Z.97, CPSC 16 CFR 1201, Cat II (400 ft-lb), and the British Standards BS 6206 (Class A, B, C). The European Committee for Standardization offer the EN12600 standard Classification of Resistance of Glazing to Impact. Often, building codes dictate that a film must have a report verifying that it has met at least one of these standards.
Solar window film is usually subject to less critical testing. However, standards are in place to maintain a level of quality in the industry. The ANSI Standards ASTM E903 and ASTM D1044-93 relate to the solar/UV transmission properties and abrasion resistance, respectively. The larger window film manufacturers use these standards to guarantee the quality of their raw materials and finished products.
Automobile window tinting reduces the visible light transmission (VLT) through car windows. This can be problematic at night, when motorists must be able to see through the windows of other vehicles in order to spot hazards which would otherwise be obstructed. Police also may want to be able to identify the passengers in a vehicle.
In many jurisdictions, there are laws to ensure darkness of films do not present a danger to motorists:
Tint Limits by U.S. state (when measured on the front side window)[4]:
| State | VLT | State | VLT | State | VLT |
|---|---|---|---|---|---|
| Alabama | 32% | Louisiana | 40% | Ohio | 50% |
| Alaska | 70% | Maine | 35% | Oklahoma | 25% |
| Arizona | 33% | Maryland | 35% | Oregon | 35% |
| Arkansas | 25% | Massachusetts | 35% | Pennsylvania | 70% |
| California | 70% | Michigan | 70% State Law | Rhode Island | 70% |
| Colorado | 27% | Minnesota | 50% | South Carolina | 27% |
| Connecticut | 35% | Mississippi | 28% | South Dakota | 35% |
| Delaware | 70% | Missouri | 35% | Tennessee | 35% |
| Florida | 28% | Montana | 24% | Texas | 25% state law |
| Georgia | 32% | Nebraska | 35% | Utah | 43% |
| Hawaii | 35% | Nevada | 35% | Vermont | 70% |
| Idaho | 35% | New Hampshire | 70% | Virginia | 35% |
| Illinois | 35% | New Jersey | 70% | Washington | 24% |
| Indiana | 30% state law | New Mexico | 20% | West Virginia | 35% |
| Iowa | 70% | New York | 75% | Wisconsin | 50% |
| Kansas | 35% | North Carolina | 35% | Wyoming | 28% |
| Kentucky | 35% | North Dakota | 50% | District of Columbia | 70% |
| United Kingdom | 70% |
Current as of 7/17/10
(Lower number is less light transmittance, thus darker tint)
Window films require few specialized tools to install on normal panes of glass and may be installed by consumers. Special care, cutting, and sizing must be taken on more complicated glass such as curved auto glass. Without the proper tools and techniques for curved glass, window filming may bubble or separate from the glass.
Window film is typically installed after surfaces are thoroughly cleaned and wiped using a formulated cleaner and a scraper blade. A simple soap solution is squirted on the glass before the film layer is applied.
Window film is typically installed on the interior side of a window.
Window tint and the adhesive that adheres it to the glass is easy to remove. All that is required is a razor blade and alcohol. Use the razor blade to remove the tint then use the alcohol with a rag to remove the adhesive.
Steam is also used to quickly and easily remove tint. This process will remove the tint and adhesive all together due to heating the adhesive up. The heat will cause it to remove from the glass. All that is required is an inexpensive fabric steamer from your local department store. Start at one edge (usually the top corner of the window) and place the steamer close but not touching the tint for a few seconds at a time. When the adhesive has heated up properly the tint will begin to lift from the glass when pulled. Slowly pull the tint away from the glass in the area that was steamed (keep in mind you are working with steam and the effect it will have on the rise in temperature). Follow this process until the entire tint is removed. Done properly, tint on the average sized window can be removed in a few minutes.
Window tint can be applied to any object made of glass. Many window tint companies will tint shopfronts windows, office block windows and house windows. Some will even tint objects such as mirrors and coffee tables giving unique looks to everyday objects.