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In our home we all want a safe and comfortable place to live, while feeling connected to outside. This is primarily done through the design and use of windows. Can you imagine a home without windows? It feels dark and confining, like a bomb shelter. The safety the dwelling provides can quickly turn into an oppressive experience without a connection to the outside. Windows create the necessary link to the world around us. In order to understand the role films play in windows, we must first look at the origins and evolution of the window.

Windows started out as a hole or slit in the wall of a home. Materials such as cloth, animal hide, and wood were originally used to cover these early windows. While this was crude, it still served the same purpose as today: connecting us to the outside, controlling the light coming into our home, manipulating the internal climate, and providing an insulation barrier. This was especially important when homes did not have electricity to power lights and air conditioners. Then came the use of glass in windows, which has its origins during the Roman times. Fast forward, our large scale windows only became possible once we were able to industrialize the glass making process.

To understand the present it is important to look at the past, and how people were using various types of film and fabric to protect and allow light into their homes. What was once animal hide is now more sophisticated. Today’s window coverings can control the amount of light entering the home from 80% to total blackout. Common window treatments we see in the home include blinds, drapes, and shades, which all incorporate film into their products. Light filtering is achieved by incorporating a metallized film into the shade structure. Other modern methods to improve energy efficiency include reflective or UV blocking films integrated into window systems and argon gas captured between window panes.

As technology continues to play a disruptive role in our lives, it is also changing the window industry as we know it. Instead of having a drape or blind, we are starting to see glass windows that can be directly controlled and manipulated through electricity. These smart windows incorporate a conductive film that incorporates a nano coating. Depending on the voltage that flows through the window, the nanoparticles will change their orientation, which regulates the tint of the window. Think of it as a dimmer for your window.

In addition to smart windows, we are beginning to see solar cells being integrated into windows. Work is being done to develop transparent solar cells that can be combined into window systems. Once again, film will be an important component in the development of this new technology. Not only will you be able to harness the sun’s energy in your home, but large skyscrapers that absorb large amounts of UV energy will now be able to harness the sun’s energy to power the building.

Whether you have a traditional blind or you decide to be an early adapter of the new high-tech smart windows, the future looks bright for windows.

Buildings have used reflective insulation since the eighties. Back then, the product was a foil-layer laminated to a bubble-layer similar to the familiar packaging material. Around 2006 a new ASTM burn test was developed to simulate a full room burn. The reflective insulation manufacturers, comprising about 10% of the insulation industry, realized that the foil / bubble product would not pass this new burn test and their market share would disappear altogether if they could not pass this critical test.

Foil based reflective insulation wouldn’t pass a full room burn test (or an improved tunnel burn test) because it would not quickly burn away from the flame. The material would remain in direct contact with the flame to the point of ignition.

The industry looked toward the past to engineer a solution for the future.

Going back to the late seventies, spacecraft used reflective insulation has for thermal protection. These constructions are slightly more complex, as you might imagine being for other-worldly applications, but are fundamentally the same. The spacecraft insulation consists of multiple reflective layers separated by non-conductive spacer material and assembled up to forty layers depending on the spacecraft operational environment.

Low-emittance (high reflectance) is the foundation of spacecraft insulation. Materials with low emittance reflect energy, heat, away from the structure. Or, they can also reflect heat back toward the structure to protect from the cold. The space industry has been using films for thermal protection for nearly three decades. Could space-age film materials be the solution here?

Yes! A brilliant company with spacecraft heritage engineered such a product. Film has been used as the reflective layer ever since and is used in all forms of reflective insulation from bubble to board and bulk.

Where should reflective insulation be used?

Reflective insulation can be used independently or in conjunction with mass insulation, like fiberglass. This increases the r-value of the bulk insulation by making it low-e (emittance). Thus, any structure using mass insulation can benefit from reflective technology. The benefit increases substantially the closer you get to the equator where radiant energy is more intense.

Furthermore, reflective insulation is ideal when there isn’t much space. Both bubble and board insulation are a fraction of the width of a bulk insulation system. In walls and other areas where space is limited, reflective insulation is often the best choice. The only thing reflective insulation needs to function is an adjacent air gap. The air absorbs the heat and acts as an insulator.

Why isn’t reflective insulation used more frequently?

The largest barrier for reflective insulation is the performance predictability. When an architect is designing a building there needs to be cost justifications, a calculated ROI. The number of variables and calculations for energy savings are complex, so architects rely on simulation models to calculate. Most of these programs do not take into account the value of the reflective insulation.

An example is the Energy Star Program. Their position is that the reflective surface has no value. Their quandary is not based on the product effectiveness, but rather the uncertainty on how to measure and predict savings. As a result, no reflective insulation product carries the Energy Star label.

Building shape, materials, air space and other variables play a part in calculating the r-value that can be achieved with a reflective product. Until the benefits of reflective technologies are incorporated into programs to calculate energy savings, the technology will never attain widespread adoption no matter the impact of the actual savings.