That is exactly what I shall do, even when I get the solar attic ventilator, which won't cost any $ to run, installed this summer or next. If inside temps above 82 force me to run the attic fan at the same time, and/or even the super-tornado fan also, I'll gladly do so before turning on the A/C downstairs. We're having a relatively cool late spring here, so maybe August won't be quite so hot as usual. This is the higher elevations of the MidWest, so there's a chance.
One thing that will help besides the extreme insulation and thermal curtains is where I can open that single downstairs window you mentioned: The house faces west, so in the worst heat of the afternoon, the downstairs east end, where that part of the structure was built around a slave cabin, gets less sun than anywhere else. That area of the backyard is in deep shade by 2 p.m. That downstairs east end is also the most insulated of all, therefore naturally the coolest. So I can open my eastern downstairs storm backdoor and the screen door will allow the very coolest outside air to be drawn in, then on upstairs to be expelled by the window fan, whole house attic fan, and if necessary also the eventual solar attic ventilator.
I'm also blessed with a deep wraparound front porch on the west and south sides downstairs, so that helps. I've grown spirea on those sides so thick and tall that except for winter, a person can sit in almost complete privacy there. Had to cut down a diseased oak tree in the front but outside the front fence I've replaced it with nearly a dozen rose of sharon and forsythia trees plus one redbud, none of which will get over 20' tall - they will soon provide another layer of shade. For winter outdoor privacy I'm about to run white lattice panels all around the front porch.
But thank you again for your suggestions. I can see where your solution to the power use would work best, now that you've explained it. Not only will I be more comfortable, I should be able to save a little more on the electricity bill, and that savings can go right back into my restoration fund. After the good front gate posts go in, I've got to get more interior work done. There's one room where most of the ceiling still drops big chunks of plaster w/o warning. As I've said elsewhere, just about another year of abandonment or rotten owners and tenants would've left this place unsalvageable. The things that a few people did try to do are not just incomplete and worn out, they were hideous to start with. For instance, they'd lowered the downstairs 10' ceilings with those dreadful white insulator squares which were starting to deteriorate and fall down. When I got rid of those in the living room, we learned that the house's original ceiling medallion was hanging by a thread and ready to drop down and kill me.
Hope I haven't rambled on too long here. Restoration of historic buildings has always been a passion of mine.
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