Not that I cannot simply go back online to obtain this information again, but I figured it would be easier to post it here and maybe also help a few people.
Most, if not all ceiling fans have a switch which changes the direction in which they spin. Due to the tilt of the blades this obviously affects how the warmer air is distributed about the room.
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hold on, me is confused.
should it blow down or up during the summer?
The terms clockwise and counter clockwise are not used (or should not be used) as they're rendered meaningless because different factories may use an opposite angle on the blade and spin the fan the other direction around. The forward direction blows down, and the reverse direction blows toward the ceiling, to tell which direction its going, stand under it and you will feel a breeze in the forward direction, if you don't feel the breeze in either direction, buy a better fan.
The normal rule is in a room with an 8' ceiling and four walls (there are exceptions to every rule) use the forward direction and medium or high speed in the summer. In the winter use the reverse direction and the medium speed. In late spring and early autumn use forward direction in the low or medium speed. In early spring and late autumn you want the reverse direction in the low speed.
What the fan is doing in this room is creating a breeze in the summer time, making it easier to breathe, evaporating perspiration and generally making you think it's cooler, this is called the Wind Chill Factor, and in the winter it pushes the hot air that gathers at the ceiling across the ceiling and down the walls resulting in a warmer room with no draft. The most common exception to the rule is the cathedral entrance / foyer / stairway area usually with a high vaulted ceiling and open to the floor above. In this area you would use the forward direction and high speed in the summer, to create your breeze, but in the winter the forward direction is again suggested this time in the slow speed so in this case you blow the hot air down and the breeze dies out above you. The reverse direction would not work here both because it's to round and about, and your lacking walls to ricochet the hot air down.
a ceiling fan cannot bring wind chill into the equation, as someone suggested here. for wind chill to be a factor in a 70 degree room, the wind would have to be at gale force or higher
Surprisingly appropriate of you to bump this post right now, considering the weather is changing.
But I've never heard anyone say that wind needs to be gale-force to make the wind chill effective. Anyone who stands under a fan could tell you that. And you'll often see weather stations say something like "50 degrees, with wind chill it's 45" when there's only a small-ish breeze expected.
As far as the Windchill, the hunter web site says exactly that.
http://www.hunterfaninternational.com/support/fan-faq.php?origx=38#6
check #6. Seems wierd but if you stand under a ceiling fan, and don't feel cooler, buy a better fan.