 Money news at 10 and 40. Apartments in the district are getting slightly bigger on average, while those in the suburbs are getting smaller. That's according to rental listing website Rent Cafe. D.C. comes in at number seven on the list of U.S. cities with the smallest average size of new apartments at 744 square feet. Rent Cafe says D.C. apartments built between 2014 and 2023 have become 0.7 percent larger, as apartments in Arlington, Alexandria and Silver Spring have become slightly smaller.