Which statement accurately describes a single hung window?

A single hung window is characterized by having two sashes, where one of the sashes, specifically the bottom one, is operable. This means that the bottom sash can be moved up and down to open and close the window, allowing for ventilation. The top sash, however, is fixed and does not move. This design makes single hung windows a popular choice in various applications, as they provide a balance between functionality and simplicity.

Understanding this mechanism is crucial for those involved in construction, window installation, or design, as it impacts ventilation strategies and the overall functionality of the window within a building's envelope. The other options would describe different window types, highlighting the importance of knowing each design's specific features.