Feather Friendly is SAFE and will NOT void your window warranty

Posted November 24th 2021

Feather Friendly is SAFE and will NOT void your window warranty

Glass is a defining architectural feature of our time. It is a robust, beautiful, and versatile material. But like most things, glass has a certain threshold. It can accommodate certain levels of stress before buckling under the pressure. Once a crack begins to form, there is little to stop it from spreading and eventually shattering.

Aside from blunt force, what causes glass to fail?

In some cases, differences in temperature between various areas on a pane of glass cause it to crack. This phenomenon is known as thermal breakage. A thermal stress fracture is easy to spot: one end of the fracture will be in contact with the edge of the window, and at a right angle to the edge of the glass.

What is 'Thermal Breakage,' and does Feather Friendly® increase the risk?

Thermal fractures are caused by flaws in the glass which are hidden by the frame, or because of temperature differences in the glass: some areas heat up faster and to a higher temperature, while other areas remain cooler, causing stress to build up at a molecular level at the intersection of these areas.

Research has shown that solid window film applications can increase the risk of thermal breakage because they cover 100% of the surface and therefore attract more heat. Film over glass can cause rapid heat absorption from sunlight in the center of a glass pane, while along the edges and frame the glass heats up more slowly. This temperature variation stresses the glass and can result in a thermal fracture (see Figure 1). Specific types of glass have varying maximum absorption thresholds, and different films have different absorption levels. Film is very safe for glass, so long as the correct film is selected for the corresponding types of glass.

Rest easy with Feather Friendly® 

Feather Friendly® is NOT a film, so you don't have to worry about thermal breakage. Feather Friendly® applications consist of individual markers placed on the outside surface of the glass to break up surface reflections. The markers are small and unobtrusive, covering only ≤ 7% of the glass in total. Therefore, heat absorption due to the presence of markers is negligible and will not lead to any significant heat stress. In 15 years of commercial and residential installations, there has never been a case of Feather Friendly® markers causing thermal breakage. 

And you can relax because Feather Friendly® will NOT void your window manufacturer's warranty. Additionally, Feather Friendly applications will NOT damage glass surfaces or exterior glass coatings, such as Solar Reflective, Low-E, or other types of glass  treatments.

Feather Friendly® markers are a convenient, durable, and safe way to prevent bird collisions, trusted by homeowners and businesses around the world. For more information, contact us or visit our website today!


We are honoured to form partnerships with organizations who demonstrate
an ongoing commitment to bird conservation.

American Bird Conservancy FLAP Canada Audubon Association of Zoos and Aquariums