A floor fan is a type of fan designed to sit on the floor. In most cases, these are pedestal type fans, but floor fans can also include box fans. All that is really required is that the fan be able to sit on the floor without tipping over.
Most all fans work on the same general principle. The head of the fan is made of curved blades that spin, and the spinning action draws air from the back of the fan in through the blades then out again in the front. This disturbance of air pressure creates a breeze. Anyone sitting in the path of the breeze will typically begin to cool off, because the breeze from the floor fan will begin drying body perspiration, and in the process will help lower body temperature. The amount of air circulation produced by a floor fan depends on both the size of the blades and the size of the motor that turns them.
Due to safety concerns, the blades of a floor fan are enclosed in screens made of plastic or wire. This makes it less likely that fingers will be exposed to rotating blades. In most cases, the screen can be removed so that the blades can be periodically dusted and cleaned.
Many floor fans have a pedestal design, which is a type of fan with a tall narrow base that is usually height adjustable. The advantage to this type of floor fan is that even though it is designed to sit on the floor, the actual head of the fan that produces the air can be adjusted so that air is being blown above floor level. This is usually preferable, because the airflow can be set so that it is at the body level of those sitting or standing inside the room. In addition, pedestal fans usually have oscillating heads, which means that in addition to spinning blades, the heads actually turn from side to side to distribute the airflow all over the room.
A box floor fan is a type of fan with a box like shape which is designed to sit directly on the floor. At their base, they typically have two support strips that serve as legs, and keep the fan from tipping over. The fan heads inside a box floor fan are usually bigger than heads in a pedestal fan, but they do not oscillate, and the only way to adjust their height is to put them up on a table. One advantage to box fans is that they can usually be placed inside open windows, which during early morning and evening, allows the fan to draw in cooler air that is outside. When it is very hot outside, putting the fan inside a window usually has no real cooling benefit.