Window! size, shape, location & number 

• A window may be defined as an opening made in a wall to provide daylight vision & ventilation.
• It consists of a frame & shutter.
• The frame consists of two vertical members called jambs or posts.
• Another horizontal member connecting post at the top called ahead.
• At their base called a sill.
• A window is normally provided with two leaves or a shutter.

The selection of size, shape, location and number of windows to be provided in a room depends on the following factors

1. Size of room
2. Location of room
3. Architectural requirement 
4. Utility of room
5. Direction of wind
6. Climatic considerations like humidity, temperature variation, etc.

Following rules may be observed while deciding the size of the window

• This total area of window opening = 10 to 20 per cent of the floor area of a room
• In hot and arid regions, opening = 15 per cent of the area of a room
• In hot and humid regions, opening =   15  to 20 per cent of an area of a room.
• In the case of a public buildings like schools, offices hospitals, etc. A minimum area of window = 20 per cent of floor area
• As adequate natural light, the area of glass panels = 8 per cent of the floor area

Some points to be kept in mind while making provision for windows in a room

• The size & number of a window should be sufficient to provide adequate light  & ventilation.
• Windows should be located opposite to each other where- ever possible.
• The window sill should be placed 75 to 100 cm. above the floor level.
• Windows provided on the Northern side permit maximum daylight.
• Buildings in the humid region need special attention for adequate ventilation of the room. Some areas of the window opening in the humid area should be highest.
• The shutter of windows in the external walls should open outside. This checks the entry of rainwater inside the room.
• Windows in the external wall should be provided with Chajja projections to prevent the entry of rainwater into the room.