Advantages of double hung window windows: Beautiful: If the opening leaf of the external casement window is too large, it is not easy to close, and the construction surface is also messy. Half of the windows on the left and right cannot be opened. In addition to the difficulty in convection of the airflow entering the room, there will also be some obstacles in the planning of some internal spaces. The high and low lifting windows are absolutely flexible in the design of height and width. The surface appears beautiful and light, the high and low window leafs can be divided by different lines, the window frame is simple, the lines are delicate, ventilation and lighting are given equal importance, and there will be no visual obstruction.