As MotorSeven was the first to say... up in the winter, down in the summer.
We have ceiling fans in every room except the bathroom, they run non-stop, pulling air up on low speed all winter. During winter, the natural circulation in a room would be warm air rising, and then falling along the (relatively) cooler walls as they cool the air... and at the floor it is pulled back to the heat source to be warmed again. It's the same basic idea as a forced air central heating system. The idea behind a ceiling fan is to enhance the natural flow, not reverse it. By blowing the heat down you are forcing the (warm) air across the floor until it contacts the (relatively) cooler walls where is forced up... bit it's cooling as it's forced up and trying to fall. This makes for uneven heat in the room... areas of warm and cool, as well as drafts that can be felt. Blowing down may seem to do a better job of distributing heat, but overall the human body will be more comfortable if the fan is pulling up, at low speed, and forcing warm air down along the walls. It's also more efficient; cold can not be transferred from one thing to another, only heat can... warm air moving faster along a cold surface (in this case outer walls) loses far less heat to that surface (like an air door works as an insulator). The wall may feel cooler to the touch, but that's because less heat is being lost to it.
In summer the natural flow in a room reverses... warm walls and windows heat the air causing it to rise and flow across the ceiling where it cools and falls into the center of the room. During summer the ceiling fan should blow down, running a bit faster than during winter because the draft actually feels good to the human body in warm weather. Again, the idea is to enhance the natural circulation, not reverse it...
We have ceiling fans in every room except the bathroom, they run non-stop, pulling air up on low speed all winter. During winter, the natural circulation in a room would be warm air rising, and then falling along the (relatively) cooler walls as they cool the air... and at the floor it is pulled back to the heat source to be warmed again. It's the same basic idea as a forced air central heating system. The idea behind a ceiling fan is to enhance the natural flow, not reverse it. By blowing the heat down you are forcing the (warm) air across the floor until it contacts the (relatively) cooler walls where is forced up... bit it's cooling as it's forced up and trying to fall. This makes for uneven heat in the room... areas of warm and cool, as well as drafts that can be felt. Blowing down may seem to do a better job of distributing heat, but overall the human body will be more comfortable if the fan is pulling up, at low speed, and forcing warm air down along the walls. It's also more efficient; cold can not be transferred from one thing to another, only heat can... warm air moving faster along a cold surface (in this case outer walls) loses far less heat to that surface (like an air door works as an insulator). The wall may feel cooler to the touch, but that's because less heat is being lost to it.
In summer the natural flow in a room reverses... warm walls and windows heat the air causing it to rise and flow across the ceiling where it cools and falls into the center of the room. During summer the ceiling fan should blow down, running a bit faster than during winter because the draft actually feels good to the human body in warm weather. Again, the idea is to enhance the natural circulation, not reverse it...
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