[djmcmath]

This is a topic that almost needs no introduction. I'm interested what ideas people have found to save energy or reduce usage in the home. My wife and I might be building a house, so ideas that we could incorporate at design time are very welcome. ... But we might end up buying someone else's house, so ideas that happen afterwards are also great.

Some random thoughts to seed the discussion:
1 - I knew a guy who built plexiglass-fronted boxes that he arrayed on his roof. The boxes were laced with small-diameter (like 1") black PVC pipes, which then fed into his hot water heater. Or in other words, he was using solar power to pre-heat the water that went into his hot water heater.
2 - I've heard a variety of variations on the theme of "move air from the basement to the attic." The basic concept seems to be to bury a large fan in the basement, perhaps even with a heat exchanger of some kind, with ventilation intake/exhaust out to the attic. Thus, cool air from the earth is exchanged with hot air in the attic, dropping temps through the house.
3 - A simpler variation on Idea #2 -- place a large fan in the attic, such that it draws a suction on the house and exhausts into the attic. When it's cooler outside than it is in the attic, fire off the fan and draw cooler air through the house into the attic.

There are a host of relatively obvious things that also come to mind -- energy efficient windows, hanging clothes out to dry, that sort of thing.

Any ideas? What do you guys do to be green?

Dan