“For someone in the market to buy, it’s an opportunity to turn back the clock on rates, but there’s no indication it’s anything but a temporary reprieve,” he said. “In the long-run, the Fed’s exit means sustained upward pressure on rates.”

5% Rate

By the end of 2014, the average U.S. rate for a 30-year fixed mortgage probably will be 5 percent, Duncan said, compared with 4.3 percent at the end of 2013. The average during the past two decades is 6.27 percent, according to Freddie Mac data compiled by Bloomberg.

Borrowing costs also defied conventional wisdom the last time the Fed pulled back on stimulus. More than three years ago, when the central bank concluded its first round of quantitative easing, housing forecasters said home-loan rates would rise on weaker demand for mortgage-backed securities.

Instead, as investors fled 2010’s European sovereign-debt turmoil, loan rates tumbled to then-record lows in November. That didn’t stem the year’s plunge in home sales, which was caused by the expiration of a federal tax credit that paid buyers $8,000.

The Fed began purchasing mortgage bonds guaranteed by Fannie Mae, Freddie Mac and Ginnie Mae in January 2009 to bolster the economy and the housing market by reducing financing costs. The strategy had never been tried before. In the first round of purchases, which ended in March 2010, the Fed acquired $1.25 trillion of mortgage bonds.

Fed Tapering

The central bank announced a second round of quantitative easing, known as QE2, in Nov. 2010. QE3 began in September 2012, with the Fed buying $40 billion of mortgage bonds and, in December, $45 billion of Treasuries a month. The central bank cut the purchases in December and again in January to $65 billion a month from $85 billion, citing an improving outlook for the labor market.

Khater, the economist, is also a home buyer who’s getting another break on rates. Even though he spends his days tracking the mortgage market, he missed 2013’s low of 3.35 percent in early May, the average rate as measured by Freddie Mac. That was close to the all-time low of 3.31 percent in November 2012.

“I’ve been thinking about buying, and I thought I had missed out on cheap rates,” Khater said.