Thanks all for your replies.   Any real life info helps!  Dean let me know if the 2 fans help move air and how much if you would.  Burl I have looked in to these, in fact I bought on and trying to make it work.  Judith I am in the same boat,  solar exhaust fan cost a lot and I am always trying to find a cheaper work around.  please let me know how the attic fan works.   Mike that is my plan to use as much passive vent as possible just wondering if a lower cost solar fan would help the process.  Again thanks all for the info