Smaller Families living in Larger Homes

I decided to have a little fun this past weekend and dig through some of Zillow’s vast database of property characteristics (yup, I’m a data junkie) for interesting trends. One of the more interesting pieces of data I found was the trend in average size of homes built by year since 1940. During the latter half of the 20th century, and into this century, the size of the average American home has almost always been on the rise.

While enduring only a slight dip during World War II and lulls in the early 70’s and 80’s, the average new US home size has increased from 1,500 to almost 2,500 square feet.  The average home size can get skewed by the mega-mansions, so we’ve also included the median home size in the chart as well. Unsurprisingly, the median home size is a bit smaller than the average home size, but you can see virtually identical trends.

With suburban growth over the second half of the 20th century, this increasing home size trend is not too surprising.  However, it presents a sharp contrast with the average household size according to the US Census (pdf).

While the homes being built in the US have been getting larger and larger, the average household size has steadily declined from 3.7 people to 2.6 people.  It begs the question, what are people doing with all of this space?