Window Film Blog
Photo of a bright room for a blog post on how window film works

How Window Film Works

As a homeowner, you’re likely always on the lookout for ways to improve your home’s aesthetics, energy efficiency, and overall comfort. One often overlooked, yet incredibly effective solution is installing window film on your home’s windows. But you may be wondering, how does window film work?

Window film is a thin, adhesive material that can be applied to the interior side of windows. It’s an elegant and ingenious solution that can significantly enhance your home’s comfort, energy efficiency, and overall appeal. In this blog post, we’ll explain how window film works its wonders to create a better living environment for you and your family.

Understanding the Technology Behind Window Film

Window film is a thin, multilayered polyester material infused with advanced technologies that allow it to reject light, heat, and UV rays passing through your windows. The film’s primary function is to block the sun’s energy from entering the home. How it does this has evolved over time:

Dyed Films

Window film does this by using various materials to block the sun. The first generation of window films in the 1960s used dark dyes to prevent heat build-up in car and building interiors.

Metallic Films

The second-generation window film that was introduced in the 1990s was a hybrid version consisting of dye to absorb the sun and metallic particles to reflect the sun’s rays. This provided a step change improvement in the performance of the film, but the metallic particles could interfere with GPS and radio frequencies.

Ceramic Films

Today, window film continues to evolve with the addition of ceramic window films. Using ceramic as a component eliminates the interference problem and offers beautiful, stable color and excellent solar control.

Since all types of window film are still on the market today, it’s important to note what kind of film you are buying to understand its properties and quality. Most films being sold to consumers online today are simple, inexpensive metallic films while most professionals opt to use higher-quality, ceramic film.

How Window Film Works

We’ll focus on ceramic window film as the leader and professional choice for residential window film. All ceramic window film absorbs some solar energy, reflects some solar energy and allows the transmission of some solar energy.


Window film absorbs a portion of the sun’s energy, converting it into low-level heat. This absorbed energy is then dissipated across the film’s surface.


The film reflects a significant amount of solar energy back towards the outside, preventing it from entering your home and reducing heat gain.


Window film selectively transmits visible light while blocking out harmful UV rays and a considerable amount of infrared heat. This way, you can enjoy natural light without the negative effects of the sun’s heat and UV radiation.

Window films are measured and regulated by the National Fenestration Rating Council which is the same agency that rates windows. The NFRC tests film against clear glass to measure the amount of solar energy absorbed, reflected, and transmitted.

Below is a comparison of what happens when solar energy (sunlight) hits a pane of clear glass and what happens when it hits a pane of glass with window film applied. For this example, the right side of the diagram is showing the performance specifications for ComforTech™ 35 window film:

Graphic comparison of how window film works versus clear glass

As you can see on the left side, 83% of solar energy passes right through clear glass, with only 9% of it absorbed by the glass, and 8% reflected by the glass.

The right side of the diagram shows how this changes once ComforTech™ 35 is applied to the glass. The film reflects 24% of solar energy and absorbs another 47% of the solar energy, letting only 29% of the solar energy pass through the window into the home.

This video also shows the comparison:

The DIY Installation Advantage

For hands-on homeowners who enjoy tackling DIY projects, installing window film is an easy and rewarding endeavor. Pre-cut kits or rolls of professional-grade, ceramic window film are available from Concord Window Film making the process straightforward. By following our installation instructions and using basic tools (or purchasing our window film installation tool kit), you can achieve professional-looking results and experience the benefits of window film firsthand.

How Window Film Works Summary

Window film for homes is a smart investment that offers a myriad of advantages, from increased comfort and energy savings to UV protection and improved aesthetics. By understanding the science behind window film and how it manipulates light, heat, and UV rays, you can make an informed decision to enhance your home. And choosing to install it yourself makes window film an economical as well as practical solution that will elevate your living space to new heights of comfort and style. Embrace the magic of window film and transform your home today with ComforTech™ Ceramic Series solar control film from Concord Window Film.

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