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.
• Frame consist of two vertical members called as jambs or post.
• 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.

Selection of size, shape, location and number of window 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 consideration 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 case of a public building like schools, offices hospitals, etc. A minimum area of window = 20 per cent of floor area
• As adequate natural light, area of glass panels = 8 per cent of 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 at 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 area 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 the rainwater in the room.