Andrew Grisafi July 1, 2020 Windows, Product Highlight, High performance, Landmark Double-hung windows are perfect for summer Andrew Grisafi July 1, 2020 Windows, Product Highlight, High performance, Landmark Double-hung windows are one of the most common, and popular, window styles. They consist of two sashes, one hung over the other. The lower sash raises and the upper sash lowers, with the potential for the two sashes to bypass each other.