It's really a return on investment thing. The longer you live in a home like that, the more you save. Unfortunately, the average home owner moves about every 7 years, and a lot of buyers aren't interested in that style of home.<quoted text>
I wish I had the money to build something like that. I'd design it with nice big windows facing south and auto shades to pull down to cut the sun exposure when not needed.
A better return on investment is a geothermal heat pump because they can be installed in most new and existing single family homes. They use the temperature of the earth to heat and cool the home, and are considered a selling point by most buyers because of low utility bills.