How many single family homes are there in the United States?

It may be that the terminology is different than single family homes. However, barring that, here are some U.S. Census numbers for you.

In 2009, the US Census Bureau reports all housing units totalling in at 130 million 159 thousand.

Also in 2009 91,241,000 total housing units for single detached and mobile homes in the United States with 79,918,000 total occupied year round. And of these, some are renters and some are owner occupied.