gonjah wrote:

Should I still be using my attic fan during still periods?
I thought they were not cost effective.

I try to not have my attic temperature exceed 100 degrees F.

So I'll turn on my attic fan when-ever the temp hits 100, wind or no
wind.

I have a 1500 sf house. How many sf should I have in

soffit vents?

You should have a soffit vent hole between every rafter joist.

If you have aluminum soffit, there's no excuse for not having perforated
aluminum soffit along the entire length of the eves. If you have mostly
(or totally) solid aluminum soffit, take it all down and replace with
100% perforated soffit:

http://www.biytoday.com/Soffit2.jpg

Just cut a hole the size of your hand with a jig saw in the existing
plywood soffit every 16" before you install the perforated soffit.

And remember that anything you do to improve soffit ventilation is
wasted if you have attic insulation jammed into the eves blocking air
flow.