House hunters are snapping up multigenerational homes, and it's reshaping how the typical American family looks

• Fifteen percent of US homebuyers bought multigenerational homes last year, the highest in nine years.
• The uptick was driven by cost savings - aging parents moving in with their adult children.
• The coronavirus recession is causing a repeat of the rise in coliving in the Great Recession.

American households are becoming one big family.

From April to June, 15% of homebuyers bought multigenerational homes, a new report by the National Association of Realtors said. That was the highest multigenerational-homebuying rate since NAR began tracking the metric nine years ago, in 2012, following the Great Recession, when many families combined households.

In 2012, 14% of homebuyers bought multigenerational homes, dipping to 11% a few years later. The percentage is at its record high of 15% as a consequence of the pandemic, NAR's report said.

Driven by coronavirus concerns, loneliness, and childcare needs, more aging parents are moving in with their children. Income loss and pay cuts also make multigenerational housing appealing for cost saving.

Playing a smaller role is adult children "boomeranging" back home, the report said. A Pew Research Center analysis of census data indicated that more than half (52%) of young adults aged 18 to 29 were living at home, NAR reported. They're not a bigger driving force of the trend because they likely moved into houses that already had enough space for them, meaning their family didn't need to buy a bigger home.

A repeat of the Great Recession

The increase in multigenerational homebuying is likely to cause the average American household size to climb.

In 2018 the average US household size began rising for the first time in over 160 years. From 1790 to 2010 it declined to 2.58 people from 5.79 people, a Pew analysis of census data found, but in 2018 it rose for the first time since 1850, to 2.63. (Pew noted that average household size was not available from 1790 to 1850.) The trend was most prominent among adults ages 35 and older.

The Pew researcher Richard Fry wrote that the decline was correlated with a decrease in the number of children women were having, as well as fewer extended-family living arrangements.

The uptick, Fry said, was likely due to several factors, including multigenerational households. From 1980 to 2016, the number of Americans living in a multigenerational household increased to 20% from 12%.

The Great Recession also left more Americans residing in shared quarters, whether with roommates or with parents, Fry wrote. The share of these households increased to 20% in 2019 from 17% in 2007, he said.

It seems that the coronavirus recession is repeating the coliving effect of the Great Recession - but this time, NAR said, the shift to multigenerational living might be permanent. That's because it's growing out of the combination of the work-from-home economy and the K-shaped recovery, in which pooling resources helps financially burdened Americans. Having an extra caretaker around for kids in remote school doesn't hurt either.