The pre-COVID-19 trend of declining home size has been universal across U.S. regions, according to NAHB's analysis of the 2019 Survey of Construction data. Nevertheless, regional differences in new home sizes exist, with some of the largest single-family spec homes built in the Middle Atlantic and some of the largest custom homes built by contractors in the Mountain division.
Looking at single-family homes started in the United States in 2019, median square footage (including finished areas of the basement and attic) was 2,300 square feet. Some of the smaller new homes were started in the West North Central division and New England, where completely finished floor space in half of new single-family homes was 2,000 and 2,100 square feet or less, respectively. Some of the largest homes were started in the Middle Atlantic, where median square footage was 2,500 square feet.
Square footage differences are substantial between single-family attached (SFA) and detached (SFD) homes. Nationwide, the median square foot area of completely finished floor space is 2,400 square feet in SFD homes and 1,800 square feet in SFA homes. The Middle Atlantic stands out for building some of the largest attached (2,400 square feet) and detached (2,600 square feet) homes. Notably, new SFA homes started in the Middle Atlantic have square footage on a par with new detached homes in the United States.
Nationwide, new single-family homes built by contractors tend to be larger, with a median square foot area of completely finished floor space of 2,400 square feet. Homes built by owners tend to be smaller, with half of them reporting square footage of 2,000 square feet or less. New single-family homes built for sale are similar in size to homes built by contractors with a median square footage of 2,300 square feet.
The Mountain division stands out for reporting some of the largest contractor-built homes. Half of these custom homes started in 2019 have completely finished floor space of 3,000 square feet or more. In comparison, custom homes built by owners in the same division report median square footage of 2,300. Though substantially smaller than custom homes built locally by contractors, these are some of the largest owner-built homes in the nation.
NAHB economist Natalia Siniavskaia provides further analysis in this Eye on Housing blog post