For maximum effect, ceiling fans rotate clockwise in cold weather months and counter-clockwise in warmer months. The proper direction contributes to energy efficiency when a room is heated or cooled.
During the winter, fan blades moving clockwise force cooler air up and pull warmer air down from the ceiling. During the summer, the ceiling fan increases air circulation. Although moving air does not cause the temperature of the room to drop, it speeds up evaporation of sweat, which has a cooling effect. Whenever ceiling fans are used, homeowners save money on energy costs. They are able to lower the thermostat on the furnace in winter and raise it for air conditioning in hot weather.