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.

There are many types and constructions of solar control and safety window films. 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, the side of the film with the adhesive is applied to the interior surface of the glass.

Typically window films are applied to the interior surface of your windows.  There are window films designed to be applied to the exterior of your windows for special circumstances such as limited access to the interior surface and triple pane windows.

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 12 to 22 years or more in some instances.  This should not, however, be assumed to be the normal expected life.

All quality window films for residential and commercial use are warranted by the film manufacturers for a minimum of seven years and up to the life of the home.

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 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.

In most cases if a house plant is already receiving adequate light the use of window film will not harm it.  New growth or flowering may be retarded, and, for a few days, a plant may go into a state of shock while it adjusts to the light change.  If a particular plant normally wilts by the end of a sunny day, it will actually thrive better with film installed.  Although there are some obvious guidelines in determining what, if any, effect window film will have on a plant (for instance, dark green plants need less light than lighter coloured ones), there is one sample test which can be done prior to film installation: merely move the plant to an area with less sunlight for a few days.  In addition, most nurseries or local agriculture agencies can advise you whether a particular plant needs closer to maximal or minimal light.

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.

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 below 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.