FAQs
In response to the many requests for a statement on the benefits of installed window film products the International Window Film Association has compiled the following information. This list may not include all potential applications and depending on the product recommendations, many products will not provide all of the benefits listed. It is the responsibility of the installing dealer, as well as the informed consumer, to determine which window film product will best suit their need. Working with an International Window Film Association (IWFA) accredited “Solar Control Specialist” assures the consumer that the dealer they are working with has successfully completed testing on important areas of technical and installation expertise.
All window films typically offer:
- Up to 99% Ultraviolet (UV) light reduction resulting in:
- Significant fade protection for furniture, carpet, draperies, wood, etc.
- Reduced fabric/textile deterioration
- Reduced exposure to UV radiation, which has been linked to certain cancers.
- Increased shatter resistance resulting in:
- Increased peace of mind
- Increased safety for family & friends
- Heavy gauge security films offer significant benefits from:
- Natural disasters such as violent storms, earthquake, high winds, etc.
- Vandalism, terrorist bombings, smash & grab, etc.
- Scratching/graffiti (glass tagging) on exterior windows, restroom mirrors, elevator doors and glass, and similar flat/smooth surfaces
- Scratch resistant hard coating protects against:
- Accidental abrasion and product deterioration from normal cleaning
- Hazy appearance typical with plastic type materials
- Performs well in all climates
- Metallized/solar control window film can provide:
- Significantly reduced solar heat gain resulting in:
- Increased comfort
- Reduced air conditioning costs
- Reduced HVAC equipment wear and tear/maintenance
- Increased fade resistance
- Glare reduction
- Daytime privacy
- Attractive accent to home and business windows
- Lower energy demands from utilities resulting in:
- Lower overall energy costs
- Decreased demand for new power generating facilities
- Decreased environmental emissions
- With “Accredited Solar Control Specialist” installations you can expect:
- Knowledgeable sales consultants
- High quality materials and installation
- Manufacturer warranties covering product failure
- Glass thermal shock fracture and IG unit seal failure coverage
- Confidence you are dealing with an industry professional
Generally, window film provides specific personal and property protection from the effects of the sun as well as added safety and security in the events that result in broken glass.
The concept of window film for use in solar control flat glass application dates back to the early 1960s. The original film design objective was to control the heating and cooling imbalances that result from solar loading. Such early films were found to reflect solar radiation back from a window, preventing the warming of inside surfaces normally hit by direct sunlight while still allowing vision through the glass.
As the window film concept was developed and improved upon, a demand developed for colored sun control films that would complement architectural design. Coloration of film was achieved through various means to produce colors such as bronze, gray, gold, amber, etc.
The energy crisis of the early 1970s prompted an interest in another aspect of window film use: the reduction of heat loss to the outside. It was discovered that polyester film tended to absorb and reradiate long wave infrared heat rather than act as a transparent medium. Through experimentation, new film materials and constructions were developed that enhanced this characteristic. These films greatly improved heat retention within a room’s interior.
The efficiencies of solar control window films are closely related to local weather conditions, building orientation, window size, and other factors such as exterior shading conditions. However, with escalating energy costs, products such as window film are increasingly valuable as an investment for commercial and residential owners and commercial facility managers.
There are many types and constructions of solar control and safety window films. These films are considered in the building industry to be “retrofit” products; that is, products to be applied to existing buildings as opposed to use in new construction. In their simplest forms, window films are composed of a polyester substrate to which a scratch resistant coating is applied on one side; a mounting adhesive layer and a protective release liner is applied to the other side. When the release liner is removed, that side of the film with the adhesive is applied to the interior surface of the glass.
1. Thermal Stress–from absorption of solar radiation.
2. Tensile Stress–from the weight of the glass itself.
3. Mechanical Flexing Stress–from wind.
4. Impact Stress–from flying objects, hail, baseballs.
5. Twisting Stress–from building or window frame sagging or settling.
The first type, thermal stress, is the only one which film may affect. The use of window films will increase the thermal stress on sunlit glass. However, there are also other factors which will increase thermal stress such as: partial shading of windows from overhangs, tightly fitting drapes or blinds, signs or decals on windows, heating and cooling vents directed at glass. In addition, different types of glass (annealed versus tempered, clear versus tinted) have different solar absorption rates and will withstand different degrees of thermal stress.
The window film manufacturers have recommended film-to-glass tables for use by factory-trained dealer installers. If a consumer is ever in doubt, he/she should request a copy of such guidelines. Listed are some glass types or conditions where the use of a solar control (not clear safety) type of window film is not recommended without extreme caution.
SINGLE PANE GLASS LARGER THAN 100 SQUARE FEET.
DOUBLE PANE GLASS LARGER THAN 40 SQUARE FEET.
CLEAR GLASS THICKER THAN 3/8 INCH.
TINTED GLASS THICKER THAN 1/4 INCH.
WINDOW FRAMING SYSTEMS OF CONCRETE, SOLID ALUMINUM, OR SOLID STEEL .
GLASS WHERE SEALANT OR GLAZING COMPOUND HAS HARDENED.
VISIBLY CHIPPED, CRACKED OR OTHERWISE DAMAGED GLASS.
REFLECTIVE, WIRED, TEXTURED, OR PATTERNED GLASS.
TRIPLE PANE GLASS.
LAMINATED GLASS WINDOWS.
1. Type of low E surface used on glass.
2. Location of low E surface in the window system.
3. The desired amount of heat gain reduction, heat loss reduction, or other film benefits.
There are two basic types of low E surfaces on glass. One of these is a conductive coating put on glass as it is being made. It gives some heat loss reduction, but does little to reduce heat gain into a building. The second type is a more complex system of multiple layers of metals and conductive coatings deposited on glass after it has been made. This type of low E glass gives heat reductions of 30% to 50% in addition to reducing heat loss. Obviously there will be more heat gain reduction using film on the first type. If there is any question about the type you may have, ask your glass company or the window manufacturer to send you the specific information about your glass.
The location of the low E surface in your window system is also very important in deciding whether film should be used. If the low E coating is on the room-side surface of the innermost pane of glass, the use of window film may reduce or eliminate the heat loss reduction of the glass itself. This may be more than offset by the heat gain reduction/heat loss reduction properties of the films to be used. Most low E window systems, however, consist of double pane windows where the low E surface faces the air space between the panes. In this case, film can be installed without eliminating the heat loss reduction benefit of the low E glass. The type of window film you choose for low E glass depends entirely on your desired benefit -whether you want to reduce heat gain, control glare, prevent heat loss, reduce fading or enhance the safety of your windows and glass doors. Carefully consider all these benefits before making a final decision.
1. Use a soft clean cloth, soft paper towel, or clean synthetic sponge.
2. Use a soft cloth or squeegee for drying the window.
3. Use any normal glass cleaning solution which contains no abrasive materials.
The availability of scratch resistant coatings as a standard feature of quality films has virtually eliminated the need for extra special precautions in cleaning.
All quality window films for residential and commercial use are warranted by the film manufacturers for a minimum of five years (certain products may have extended coverage). The warranty includes an address to contact the manufacturer directly should any questions arise either before or after the installation of the window film.
1. Ultraviolet Light
2. Visible Light
3. Heat and Humidity
4. Chemical Vapors (including ozone)
5. Age of Fabric
6. Dye Fastness
Clear single pane glass (1/8″ to 1/4″) will reject 23-28% of the ultraviolet light from the sun. Insulated glass is slightly better, rejecting 36-41%. Window films installed on glass reject 95-99% of solar ultraviolet light.
Different types of clear glass and window systems will reject 13-29% of the solar heat. With window films, 80% solar heat rejection can be obtained.
No window film can eliminate fading. It can, however, offer maximum protection from fading due to solar ultraviolet light and solar heat.
