In the summer, ceiling fans are very effective at lowering the apparent temperature by making use of evaporation. When you are hot, you perspire, perhaps only a small amount. This is the body's way of cooling off - Evaporation of the perspiration pulls heat away from your body. Circulation of the air rapidly increases evaporation. The more evaporation, the cooler the apparent temperature. This means the thermostat on the A/C can be set higher - saving you money.
With the reverse switch set for a downward airflow, in almost all cases this is counter-clockwise (looking up), running your ceiling fan on high speed creates a turbulent column of air. This cone-shaped area of maximum airflow is relative to the area and pitch (angle) of the blades, as well as the RPMs of the motor, hence the three speeds.




Use of the ceiling fan in winter, well, seems a bit strange to some, but actually it too can save you money on your heating bills. Heat rises. A large amount of heated air can collect in a large room with high ceilings before it can even be felt. In cold climates, where possible, heater vents are put in the floor. This is the most effective way to heat a room, because the air will rise. In a room with a 16' cathedral ceiling and the thermostat set at 68 degrees F - the uppermost 3 feet can be 90 degrees or higher before the heater shuts off. An incredible waste of energy.
With the reverse switch set for an upward airflow (clockwise), running your fan on low speed will force the heat accumulated at the ceiling down along the walls where it must rise again. This mild circulation of air provides a more evenly heated room, shortening the time it takes the heater to work. (Low speed is highly recommended to avoid drafts.)



For the energy use of a light bulb, the ceiling fan is a very cost effective way to be comfortable.