From the US Dept. of Energy:
The size of new U.S. single-family homes completed in 2009 declined, dropping to a nationwide average of 2,438 square feet and reversing trend of the past three decades, according to a National Association of Home Builders (NAHB). New single-family homes were almost 100 square feet smaller in 2009 than they were in 2007, according to recently released U.S. Census Bureau data. One reason for the drop, NAHB noted, was homeowners’ desire to keep energy costs in check. This growing energy-efficiency consciousness is one of many trends that the association said was likely to continue.
Continue reading: Report: Home Size is Declining, Energy Efficiency a Factor