I would love to put a white roof on the non-visible parts of our house (one of the ideas mentioned there) A white metal roof would be quite costly though, for our situation. (big house, high roof and high cost of labor/materials right now.)
We have the whole house fan, but its been too horribly muggy these past few days to bother.
By the way, upgraded attic insulation is a wonder. Payback time can be as short as 1-2 years, and it is usually DIY.

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Last summer, we lived in the (daylight) basement for 2 months and kept the AC off.