I'd like to throw in the fact that the whole "you should draw air upward during the summer time" thing is complete crap. I live in a hot place and I'm telling you that you
always want the air blowing down on you. But the difference should be obvious--if there's not a noticeable difference between the two directions on top speed, then it sounds like your fan blades aren't angled well and are just slicing horizontally through the air. Pro tip: don't try to bend them to a sharper angle while the fan is spinning.