What type of window has two separate parts that slide up and down on a track?

The double-hung window is characterized by its two separate sashes that can slide vertically up and down along a track. This design allows for airflow control, as either sash can be opened independently or both can be adjusted for optimal ventilation. This type of window is commonly used in residential architecture due to its functional versatility and ease of cleaning, as both panels can be tilted inward.

In contrast, a casement window is hinged on one side and opens outward, while an awning window, which also hinges, is positioned at the top and opens outward, providing ventilation without letting rain in. A sliding window consists of one or more sashes that slide horizontally, differing from the vertical movement found in double-hung windows. Understanding these distinctions is crucial for recognizing the specific functionalities and aesthetic appeal of different window styles in architectural designs.