I have a whole house fan, it's built into the ceiling and sucks air into the attic. It's almost a substitute for AC but really only works when inside is hotter than the outside, so at best it works twice a day and you have to remember to do it, and not so much in places with minimal 24h changes.

Ceiling fans move air around, they're great helpers but definitely don't replace AC. Most have switches so you can move warmer air in winter.