Ah, the whole house fan. I grew up in an area with 90-100 degree days/50 degree nights without AC, and my parents eventually got a whole house fan.

We had it installed in the ceiling in our hallway in a 4 bedroom house. I didn't care for it for a couple reasons:

It was dusty around where we lived. This means it was really good at sucking said dust into the house. Made everything get dirty faster.

Even when it was on at night, it didn't really seem to cool off the house much. Sure, if you sat in the wind path of your open windows, it was 50 degrees. If you weren't, it was still pretty warm. I'm sure it was really good at cooling our attic off though.

Part of me wonders if the fan was too large for the house to be effective.