San Francisco has approved the construction of tiny apartments as small as 150 square feet. Previous zoning required a minimum of at least 290 square feet. New York City is considering a similar measure.
Meanwhile, construction of 200-square-foot single-family homes is growing popular in Washington, DC. Homes of 150 to 200 square feet sell for $20,000 to $50,000, or $133 to $250 a square foot.