That’s just the median, of course. But the share of newly built homes that are at least 4,000 square feet is now at 10 percent, equaling the series’s peak in 2008, after having dipped slightly immediately after the crash. The share of homes that have at least four bedrooms is also at a historical high, at 44 percent. That’s almost twice the share in 1973.
Some of the growth in the size of houses in recent years may reflect the changing composition of home buyers. If the kinds of people able to afford newly built single-family homes are increasingly higher-income, we would expect that the kinds of houses being built might be increasingly higher-end, and thus larger. The size of the typical unit in a multifamily building — which has had a much stronger recovery than the single-family home market, perhaps partly because so many Americans now can’t afford to buy or rent a standalone home — is below its peak in 2007.