These exterior attachments, often affixed above residential window frames, serve as protective overhangs. Functionally, they deflect precipitation away from the window surface, minimizing water streaking and potential damage. An example includes an acrylic shield mounted over a double-hung window to prevent rainwater from directly contacting the glass and frame.
The implementation of these devices can contribute to several advantages. They can reduce the likelihood of water infiltration, which helps prevent mold growth and structural decay. Furthermore, they aid in maintaining exterior cleanliness by limiting water marks. Historically, simpler forms of these protections, such as extended eaves, have been architectural features to protect structures from the elements.