A 'silver tsunami' of homes to hit the market by 2037

Over a quarter of occupied homes are expected to become available in the next two decades with baby boomers aging out, according to Zillow.

This follows the largest annual housing inventory decline in 18 months, which came in October. Rising labor and material costs boosted the ongoing housing shortage issue over the past decade, pushing up rent prices and home values.

Boomers' aging out suggests this could reverse course in coming years.

U.S. residents aged 60 or older own nearly a third of all properties today. Between 2007 and 2017, seniors released about 730,000 homes each year. That number should climb to 920,000 units from 2017 to 2027 and 1.17 million units from 2027 to 2037, putting about 20 million properties — 27% of all currently occupied homes — up for sale.

So many properties are expected to be released, it could actually lead to excess supply in certain regions akin to the nationwide new-home building of the 2000s' housing bubble.

"Retirement hubs like Florida and Arizona are likely to feel the sharpest impact," the report said. "If demand erodes because fewer people choose to retire there in the coming years, those areas might end up with excess housing. Also heavily impacted will be regions like the Rust Belt, which saw younger people move away in recent decades, leaving older generations to make up a larger share of the population."

Seven metro areas project shares over 30% of senior owner-occupied homes to be released by 2037. The combined statistical area of Tampa-St. Petersburg-Clearwater, Fla., leads with 33.2% of homes. Next came 32.6% in Tucson-Nogales, Ariz., and 31.9% in both Miami-Fort Lauderdale-Port St. Lucie and Orlando-Deltona-Daytona Beach, Fla.