Which type of window consists of two sashes sliding vertically?

The correct option is Option C.

Double-hung Window:

• A double-hung window is characterized by two sashes—an upper and a lower—both of which can slide vertically within the frame.
• This design allows either sash to be opened for ventilation, offering flexibility and better airflow.
• It is one of the most traditional and widely used window types in residential buildings, especially in regions with changing seasons, as it allows warm air to escape through the top and cooler air to enter through the bottom.

Additional InformationCasement Window

• A casement window is attached to its frame by one or more hinges at the side.
• It opens outward or inward like a door, typically using a crank or lever. These windows are often used to allow maximum ventilation and unobstructed views, but they do not slide vertically.

Sliding Window

• Sliding windows have sashes that move horizontally along a track.
• They are commonly used for wide openings and are easy to operate, but they do not involve vertical sliding of sashes.

Fixed Window

• Fixed windows are stationary and do not open or close.
• Their primary function is to provide light and external views.
• Since they have no movable parts, they are not used for ventilation and definitely do not have sliding sashes.