U.S. homes are expected to gain more than $1.3 trillion in cumulative value in 2012, the first annual gain in more than five years and the largest since 2005, according to Seattle-based real estate tracker Zillow.

In Boston, homes are expected to gain approximately $15.7 billion in value for 2012, after losing $7.8 billion in 2011.

Worcester homes are expected to gain $511.7 million in value, and Cape Cod homes will climb $425 million in 2012. Springfield homes, however, are projected to decline $334 million in 2012.

Overall, U.S. homes will have gained approximately $1.35 trillion in cumulative value during full-year 2012, to a total of approximately $23.7 trillion, up 6 percent from the end of 2011. Last year, cumulative home values fell almost $792 billion from 2010.

The gain in cumulative home values is the first annual increase since homes gained $483 billion in total value in 2006. Cumulative home values fell each year from 2007 through 2011, with the largest drop coming in 2008, when homes lost more than $3.2 trillion in value, according to Zillow.

"This gain in cumulative home values is welcome and long-awaited, after years of cumulative value declines," Zillow Chief Economist Stan Humphries said in a statement. "After a sluggish 2011, the housing market really turned a corner in 2012, as historic affordability and sustained investor interest helped keep demand at a boil."

"We expect value gains to continue into 2013. As home values rise, and more homeowners are freed from negative equity, we can expect a continued slow transition to a more normal housing environment driven by local market fundamentals and conditions," he said.