What type of window features two sashes that move past each other in a vertical plane?

The type of window that features two sashes moving past each other in a vertical plane is known as a double-hung window. This design allows for both the upper and lower sashes to be opened independently, which provides versatility in ventilation and ease of cleaning. The ability to open both sashes also allows for air to flow through the window more effectively, as it can be drawn in from one sash while being expelled from the other. This characteristic makes double-hung windows a popular choice in various architectural styles, as they can complement both traditional and modern designs.

In contrast, a single-hung window only has one movable sash, typically the lower one, while the upper sash remains fixed. Casement windows are hinged at one side and open outward, usually operated by a crank system. Horizontal sliding windows slide open from side to side rather than vertically. Understanding these distinctions is essential when recognizing different types of windows and their operational characteristics.