An article in the July/August 2009 issue of The Atlantic mentions efficiency improvements in housing as a way to ease our reliance on carbon.

The problem:

slightly more than half of the energy consumed in the United States goes to buildings: 12 percent for constructing them, and 39 percent for heating, cooling, and lighting them

According to Marc Porat, "a serial entrepreneur in the 'built environment' sector" and Chairman of ZETA Communities:

“The easiest, fastest, most effective way to reduce energy demand is to hit buildings”

Porat’s Serious Materials makes high-efficiency windows and low-energy drywall; CalStar Cement uses fly ash to make low-carbon bricks and cement; Zeta Communities puts up town houses with minimal carbon footprints.

(From ZETA's site: "ZETA's core business is factory-built production of residential and non-residential structures.")