We're going to put a ceiling fan with a light in our living room, but we don't know if we should get a 4-blade or 5-blade fan. Do the 5-blade fans cool better than the 4-blade fans?
I don't think it really has as much to do with how many blades you have as it does with how wide the blades are. Wider blades are going to put off more cool air.
Ceiling Fans 
Linear Mode
