The Many Benefits of Window Film

Here are just a few benefits of window film for windows, doors and skylights:

  • Upgrade existing glass in good condition to improved energy standards
  • Helps to hold glass shards or granules together when impacted or broken
  • Prevents 99% of the sun’s harmful UV rays from passing through the glass
  • Reduces solar heat gain from the sun by as much as 85%
    Installations may last 15 years or more
  • The cost to have window film professionally installed is about 1/10th the cost of replacement windows

In response to the many requests for a statement on the benefits of professionally 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.

Here are some common questions about window film:

Can windows with window film installed be washed or cleaned?
Windows with film applied are easily cleaned without damage to their appearance as long as a few common-sense guidelines are followed:

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.

Can window film be installed on low-e windows?
Whether window film should be used on low E windows and how much you will benefit depends on three factors:

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.

Can window film prevent fading?
It can reduce the impact of the sun’s UV rays or spectrum by 99%, which is a cause of fading. There are six factors affecting fabric fading:

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.

Will window film lead to glass breaking?
Glass breaks when stressed. There are five types of stress which may cause glass breakage:

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.

How long does window film last?
The effective life of window film will vary by the type of film, type of glass, window construction, compass orientation of glass, and in which part of the world the building is located. There are documented cases of film lasting 15 years or more.
All quality window films for residential and commercial use are warranted by the film manufacturers. The warranty includes an address to contact the manufacturer directly should any questions arise either before or after the installation of the window film.