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For the summer, you should have the fan running in a counter clockwise motion - this pulls the air down from the ceiling and gives you the cooling effect of the fan on the skin.
For the winter, warm air rises - by running your fan in a clockwise direction this will pull air up from below and force the warmer air down into the room. It directs the air up and then down along the walls as you do not want the air blowing directly on you in the winter as that will cause a cooling effect.
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