In winter, a ceiling fan should turn in a clockwise direction, as viewed from below, to enhance home heating. Using a slower speed helps avoid a wind-chill effect in cooler temperatures.
During colder months, a ceiling fan can be used to circulate the air in a room and eliminate hot or cold spots that result from unequally insulated exterior walls, windows, doors and heat sources such as furnace air registers. Additionally, hot air rises and naturally accumulates high in a room's area near the ceiling. A properly rotating ceiling fan forces the warmer air to circulate around the room in a pattern of flow across the ceiling, down the walls and ultimately back upward to the fan. This vertical pattern of circulation helps to maintain a consistent temperature throughout the room, and this constant temperature is warmer than the cooler air that pools low in the room when the fan is not active.
Standard ceiling fan blades are attached to the motor shaft so that clockwise rotation pushes air up toward the ceiling and counterclockwise rotation pushes air down into the room's center. Most ceiling fans have a switch that is used to reverse the fan's rotation during cold months.