RENO, Nev. - After two days with his same-sex marriage position in the spotlight, President Obama today sought to shift focus back to the economy, visiting a neighborhood hit hard by the housing crisis, to claim success at helping struggling homeowners and call on Congress to do more.

Standing in the driveway of a home whose owners had recently refinanced their underwater mortgage, Obama credited rule changes for government-backed loans that he imposed six months ago with allowing more Americans to benefit from historically low interest rates.

"Since I've made this announcement, refinancing applications have gone up by 50 percent nationwide and 230 percent here in Nevada alone.  That's the good news," Obama said. "People are taking advantage of this. That's what we want to see."

He also called on Congress to enact legislation that would allow more homeowners, not just those with government-backed loans, to refinance.

"I'm calling on Congress to give every responsible homeowner a chance to save an average of $3,000 a year by refinancing their mortgage," Obama said. "It's a simple idea, it makes great sense, and I know it will have an impact."

Obama met with homeowners Val and Paul Keller before his remarks.  The couple had previously not been able to refinance their $168,000 mortgage, which they'd held for 14 years, despite keeping up with monthly payments.

Thanks to changes implemented by the administration six months ago, the Kellers were able to refinance last year, saving them $240 a month.

"The reason the Kellers were able to refinance is because the only thing that we could do without congressional action was to give opportunities for refinancing for folks with a government-backed loan, an FHA-backed loan," he said. "But in order to expand that opportunity - we want to include everybody, people whose mortgages aren't government-backed - we've got to have Congress move."

But while Obama sought to claim credit for a surge in refinancing, it's unclear how much of the influx in applications is directly attributable to his policy changes, which applied only to a select group of homeowners, versus average Americans just trying to take advantage of lower rates.

Moreover, as his critics note, it's unclear whether the majority of those applications have been approved by lenders and therefore have resulted in savings for homeowners.

"How many people in Nevada fit the profile of the Kellers that actually got help and are a success story?" questioned U.S. Rep. Mark Amodei, R-Nev., who is a supporter of Mitt Romney.

"So to come in here and ask people to ignore that and say, I'm going to sit in the home of some folks that it's actually helped, is like, Hey, congratulations for finding some of those folks," he said on a conference call with reporters.

"But if you think the answer is a continued government refinancing deal to the ignorance of the economy and western Nevada, I quite simply disagree with your philosophy and I'm talking to the president here," he said.

Neither the administration nor the Mortgage Bankers Association, which tracks the data, could say how many homeowners have been able to refinance under the new rules implemented in October. And experts conceded that more applications do not necessarily translate to lower rates.

"We track applications, which can either be accepted or denied," said John Mecham, a spokesman for the Mortgage Bankers Association.

"The data [showing an increase in applications] is based off an index … so we can track changes over time, but don't have actual numbers," he said.

In October, during a visit to Las Vegas, Obama announced a series of administrative changes spearheaded by the Federal Housing Finance Agency that have allowed select homeowners whose mortgages are backed by Fannie Mae and Freddie Mac, who have good credit and no late payments in the last six months to refinance without getting a new appraisal or full credit check.

The FHFA estimated at the time that the initiative could help thousands of homeowners.

The administration says the costs and "red tape" to refinancing remain prohibitively high, particularly for non-government-backed mortgages, and is now pushing legislation to expand the reforms to the broader housing market as part of its "to do list" for Congress.