Horizontal Slider windows open with the sash sliding left or right. Some people find sliding windows easier and faster to open than crank-style windows. Since they open and close without protruding, horizontal sliders are an excellent choice for rooms facing walkways, porches or patios. Horizontal sliders are a favorite for contemporary style homes and are also popular for satisfying bedroom egress requirements. In a single slider, one sash slides to open. In a double slider, both sashes open. Double sliders are great for providing air circulation, particularly if there is only one window in the room.