To build Green doesn't have to cost a lot of money. Just consider the placement of you home on your lot and the difference it can make.
Here are pictures of the south side of the house, taken at Noon. You'll see that on December 21st, when the sun is lowest in the sky, the wall has fully illuminated windows so the house captures the maximum BTU's possible:
On March 21st, Spring Equinox, the south windows are partially shaded and by May 2nd, all of the south windows are completely shaded the entire day as the sun rides higher through the sky:
Complete shading will continue through most of the summer:
By September 21st, the shading will be back to the March 21st levels. Complete illumination will start again in early November:
It's amazing to see how well it works. It is so nice to be warm in the winter and cool in the summer just by being mindful of the sun!!