Baby boomers continue to own many of the country's large houses, even after their households have shrunk to one or two people. And while some are happy in their large homes, others say they want to downsize, but it just doesn't make sense financially.

Smaller homes can cost more if they're newer, or are part of a community that provides extra services. Some metro areas have few one-story homes, making them hot commodities.

"You've got a pure housing mismatch for older homeowners. They are mismatched physically or functionally with the house that they're in," says Gary Engelhardt, professor of economics and faculty associate in the Aging Studies Institute. "That's because it's multifloor living. It's stairs. It's also other upkeep."

Engelhardt says one policy approach that can deal with what's happening is to encourage building housing that's well suited to older Americans. "You promote the construction of new residential units that are going to be ADA compliant, that are going to have universal design and all the types of features that lend themselves to a better match of functionality at older ages," he says.

Read more in the NPR article, "Many baby boomers own homes that are too big. Can they be enticed to sell them?"