Generally, the thicker the glass, the more noise reduction. Since soundproof windows typically have two layers of glass in them, each one can vary in thickness depending on your needs and the source of the noise. Additionally, the air gap between the two panes of glass can also vary in thickness, increasing the window’s overall noise reduction. Typically each pane of glass will fall between ⅛” and ¼” thickness. DefenseLite polycarbonate is ⅜” thick, but it is applied on the exterior of existing windows and is nearly invisible upon installation. Since our polycarbonate is so thick, in many cases it offers superior noise reduction over thinner glass solutions.