A window of this type features two sashes, one fixed in place and one that can slide vertically. Typically, the lower sash is the movable component, allowing for ventilation from the bottom portion of the frame. This design distinguishes it from other window styles where both sashes might operate.
This window configuration provides a balance of functionality and cost-effectiveness, making it a popular choice in residential construction. Its simple mechanism contributes to ease of use and maintenance. Historically, this design offered an efficient way to introduce fresh air while maintaining a degree of security and weather protection.
