Advantages: it does not occupy indoor and outdoor space, freely controls the opening area and is simple to operate. Especially suitable for window sills. Folding open doors and windows are suitable for large spaces, and they slide along the track when opening and closing, which is convenient to operate.

Disadvantages: ① The maximum opening can only reach1/2 of the whole window area; (2) In stormy days, windows can only be closed without ventilation. (3) Cleaning is difficult, and it is difficult to wipe the outward side of the glass. (4) poor sealing, poor air permeability, dust easy to enter. The lower slide rail of the window frame slides back and forth, and the space on the upper side is large, and there is a gap between the pulleys on the lower side, so the heat loss is large.

2. Vertical hinged window

Type: generally divided into two ways: inner casement window and outer casement window, and also divided into two ways: single fan and double fan.

Advantages: Cleaning the window glass is simple, safe, flexible and convenient. The casement window is a traditional and simple opening method, which does not occupy indoor space. The inner casement window can realize two functions of hanging, tilting upward and opening horizontally inward through hardware linkage, which can gently replace indoor air. Generally, a good rubber sealing strip is used between the sash and the window frame, which has excellent sealing performance.

Disadvantages: occupying indoor and outdoor area. If it is open inside, the window can easily break the child's head. It pollutes the environment and easily causes rain and dust to invade the room.

The energy-saving effect of casement window is far superior to that of sliding window, which can be called "energy-saving window". For the balcony with increased depth, the floor-to-ceiling sliding window is perfect, which not only increases indoor lighting but also strengthens the connection between indoor and outdoor.