by Calculated Risk on 9/30/2010 01:34:00 PM

From The Economist: Cramped quarters: As children postpone their departure, households get larger

Image credit: The Economist

[A]fter shrinking for decades, households have started to grow. Last year the average household had 2.59 people, up from 2.56 two years earlier, marking the first increase since 1993.
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Much of this is almost certainly a response to the recession and the surge in unemployment. For young people who have lost their job or cannot find their first one, living with their parents becomes more attractive.

Note: This data comes from the 2009 American Community Survey, and many caveats apply.

As Greg Ip noted, the overall U.S. population is still growing, and at the current growth rate that would usually mean the demand for over 1 million additional housing units per year. However since many people are doubling up (or as we always joke - have moved into their parent's basement), this keeps the demand for housing units down.

This might seem like a small increase in the number of people per household (from 2.56 to 2.59), however that has a significant impact on the number of housing units needed.

Some rough numbers: If we assume a population of 300 million, the slight increase in household size would suggest about 1.3 million fewer housing units were needed. (300 million divided 2.56) minus (300 million divided by 2.59) equals about 1.3 million. This is more than offset by the growing population over this two year period, but this shows why the excess inventory has remained very high even with a series low number of new housing units being completed.

We all expected this during the recession, but it will be important to watch if the household size starts to decline again.