A vertical sliding window, also known as a single hung window, is a type of window where only the bottom sash (the part of the window that holds the glass) is movable, sliding upward to open while the top sash remains fixed. This design is common in residential and commercial buildings and offers several advantages, including ease of operation, energy efficiency, and space-saving functionality. Vertical sliding windows are often found in traditional and contemporary architectural styles and are available in various materials such as wood, vinyl, aluminum, and fiberglass. They are popular for their classic appearance and versatility in different settings.