Choosing The Right Window Film For Your Home

Today’s window film industry and the types of film available can be quite complex. What isn’t complex is how much a homeowner can reduce energy loss, which is between 30 to 50 percent. This is done by maintaining a home’s cool temperatures during the summer by blocking out the heat, and in the winter, holding heat within the home. The value of window film doesn’t stop at cost reduction. It is also bought for security reasons as it prevents glass from shattering.
Even with all of this knowledge, before choosing the right window film for your house, do your research. Know what types of window film are available. For instance, some window films are made up of metallic materials and therefore are reflective. Reflective films do just this, reflect the unwanted solar heat gain away from the window before it can be absorbed. The film is also designed to absorb the solar gain as well, taking that heat and dissipating it. Before choosing reflective film and of you live in a neighborhood with a homeowners association, check and make sure there aren’t any rules or objections to having shiny or mirror-appearing coatings on your windows.

How do you know how shiny or reflective your tint could be? You can look at a sample in a sales office or know the higher the reflectance, the shinier the window will appear.

But reflection isn’t everything. You will also want to consider LSG or light-to-solar-gain-ratio. This ratio determines the amount of light the film is able to filter while being able to transmit light. The right window film will allow plenty of sunlight into your room to keep it naturally illuminated while blocking out heat damaging UV. The film will also preserve your views and the architectural design of your home.

When shopping for LSG films or those that are reflective, check also the visible light reflectance or VLR. This should be 15 percent or lower on both the interior and exterior sides of the film if you want something that doesn’t look non-reflective. The higher the VLR the more reflective the film will be.

If you live in a hot climate, you may want a high LSG film that exceeds 1.0. Then look for the lowest SHGC value you can find in a film that is not objectionably dark to the eye.

When measuring window film visually, remember that the human eye is very good at seeing small differences in brightness, but the eye is not that good at perceiving absolute brightness levels. One’s eye also adapts to changing levels, and you can see just as well in a room illuminated with 1000 lux of light as in one having 1500 lux. When looking at film samples, the tint may appear darker in the store but when the tint is put over a large piece of glass, such as in your home, you may not even notice the difference. The color change is subtle.

There are rules of thumb for VT value that you can use as well. They include:

For moderately well shaded, vegetative exterior scenes, keep the visible transmittance (VT) value above about 0.45 to 0.55.

For a bright, unshaded exterior scene, especially one with bright, highly reflecting surfaces in view outside the window, choose lower VT values, in the range from 0.25 to 0.4.. If the application is for a sunroom, the result might be too dark for you. For a sleeping room, however, the somewhat darker film can help avoid window-produced glare.

Choosing the right window film for your home, just requires a little bit of homework.

By: John O Brien