John Harlow wrote:
What would be the problem with ducting cool air from under a house to
the attic in warmer months to help with cooling, and just the
opposite in the winter to help with heating?

I doubt if you would gain all that much and you may have some moisture
issues. Cool moist air is not comfortable.

You would gain some, but you just don't have enough area to transfer
enough heat (in or out) with just the basement walls. Right now it cools
the basement well, but you don't have much air exchange. In addition a lot
of the cooling is due to evaporation from the walls. That just adds to the
humidity.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math