I'm finding this thread fascinating reading. You obviously have folks here interested in energy and energy conservation. You obviously have folks who are "handy" and have done stuff to their house themselves.
Also the concept is simple. And yet, you have wildly differing theories. (I am a new homeowner (former apartment dweller), am NOT handy and cannot add any information to thisdiscussion - sorry).
I WOULD think though that there SHOULD be some good objective material in quality home construction / maintenance books and/or the library and/or on the internet **IF** you can figure out where to look and which advice to trust.
....
I wonder exactly the opposite, and plan on experimenting with that this summer. I am in my parents' well-built 55 year old house with a crudely finished half basement with no insulation aside from a little paneling on half of one wall.
The basement stays NICE and cool in the summer, even with the A/C off. (The furnace (with the air conditioner unit attached) is in the basement, FWIW).
I am wondering about:
1). Having a powerful fan try and blow much of that air up the stairs by main force (since cold air will just sink if left alone). This will cost maybe 50 bucks for the fan, a bit of inconvenience of it being in the way, and about the electricity of running a light bulb. (I am also thinking this might work MUCH better if there is a ceiling fan in the room upstairs that the stairs enter into).
2). I am wondering if some more sophisticated circulation system (like say a whole-house fan and a laundry-chute hole type of arrangement -- to draw LOTS of cool air directly upstairs. This would be a fairly expensive arrangement, it seems to me.
(A friend has a whole-house fan to blow air from the house into the attic in the summer and he says it's really great. The fans might run $700 he says, so the big deal is constructing the hole and the fallout from that.)