During the summer you want the fan to blow cool air straight down, in a counter-clockwise direction. However, during the winter season, having the fan rotate in a clockwise direction will allow air movement; pulling cool air up.
Most fans have a reverse function, either on the fan motor or on the remote/wall control, allowing the fan to function during all seasons of the year.
Ceiling fans should work on low speed during the winter…and remember, the fan should always work at higher speeds as it gets warmer in the summer!
Ceiling fans are great helpers in reducing the cost of electricity for cooling/heating systems.