The announcement seems a signal that the Fed is confident that housing is turning around — and that by itself could make home builders, mortgage financiers, real estate agents and buyers feel more confident as well, analysts said.

“There’s definitely a sense at the Fed that this channel could be one of the more promising channels,” said Joseph E. Gagnon, a senior fellow at the Peterson Institute for International Economics. “Sometimes people are looking for a reason to be optimistic,” he added.

On Thursday and Friday, financial markets cheered the Fed’s announcement. Stocks climbed, as did the price of many of mortgage-backed securities.

But housing analysts cautioned that the Fed effort was no panacea. Millions of homeowners owe more on their mortgages than their homes are worth, leaving them in no position to sell. Millions more are unemployed or underemployed, and unable to afford a home. The foreclosure crisis is continuing and credit is tight, leaving many people who would like to buy a house unable to get a mortgage.

Jed Kolko, the chief economist at Trulia, a real estate analytics firm, anticipated a muted effect on sales.

“The big obstacles for people who want to buy are saving enough for a down payment and qualifying for a mortgage, because credit is still tight,” Mr. Kolko said, saying that the Fed program would not directly address those problems.

Mr. Kolko and other analysts also noted that hundreds of thousands of Americans had already refinanced their mortgages to take advantage of rates near record lows. (Mr. Bernanke, for instance, refinanced his Washington home last year, taking out a 30-year mortgage with a 4.25 percent interest rate.) That leaves the pool of homeowners potentially looking to refinance smaller than it otherwise would be.