New single-family houses have been getting bigger, according to the Census Bureau. Those built in 2017 had a median of 2,426 sq. ft. of floor area. While this is not the record high, it's close. The record was set in 2015 when new single-family homes had a median of 2,467 sq. ft.

Median sq. ft. of floor area in new single-family houses
2017: 2,426
2016: 2,422
2015: 2,467 (record high)
2007: 2,277
1997: 1,975
1987: 1,755
1977: 1,610

Single-family homes built in 2017 are 51% larger than those built in 1977.