Can you put a whole house fan in an attic if you live in it?
I love whole house fans , have now installed them in 4 houses and 2 garages. As noted they can only reduce temperature to the outside temperature. But that works well with a night temperature below 70F and a day temp above 80F , running an hour or so in the morning. Ideally you need to install it in a gable for your situation. You may want an insulating foam panel to put over the louvers when the fan is not on as louvers leak air. I recommend a belt drive as the direct drive turn the fan faster making significantly more noise. As noted , windows need to be opened to let air in,; window adjustment also lets you focus the cooling.