Thank Ben Bernanke for breaking the 5% mortgage-rate barrier.

Rates on 30-year fixed mortgages have remained at record lows since last week when the Federal Reserve announced its plan to purchase up to $300 billion in Treasury securities over the next six months and an additional $750 billion of mortgage-backed securities through the end of the year.

For the week ending March 26, conforming 30-year fixed mortgage rates averaged 4.85% -- the lowest rate since Freddie Mac started conducting its Primary Mortgage Market Survey in 1971.

"[The Fed s actions are] going to keep mortgage rates low through the rest of the year and that is going to have positive implications for prospective home buyers, says Greg McBride, senior financial analyst at Bankrate.com. In fact, it's hard to find a better buyer's market right now. Not only are mortgages being granted at record-low rates, but there's also a glut of unsold homes on the market selling at a much lower price than they would have a year ago.

Homeowners looking to refinance, however, face a bit of a dilemma: Refinance now and miss out on the possibility that rates will drop even further. Or, decide to wait and miss out on today s record lows -- or perhaps be unable to refinance altogether.

For homeowners trying to figure out what to do, here are some factors to consider that should help you decide:

Home prices

Are home prices in your area still in freefall? If the answer is yes, holding out for lower rates is a dangerous proposition, warns McBride. If you wait too long, sure, rates might drop but then the value of your home may fall to the point where you might not be eligible to refinance, he says. You could win the battle, but lose the war.

Equity in your home

Even with President Obama s Homeowner Affordability and Stability Plan in place, homeowners who owe more than 105% on their home s current market value are not eligible for refinancing. In addition, to qualify for the stimulus your mortgage must be owned or guaranteed by Fannie Mae or Freddie Mac. Everyone else must shop around. And in those cases, lenders will require that you have at least 10% equity in your home, according to Keith Gumbinger, vice president at HSH Associates.

Refinancing costs

If you have a fairly good idea of the new loan s terms and closing costs, crunch the numbers in our Should You Refinance?

Adjustable-rate mortgages

If you have a prime adjustable-rate mortgage that s about to reset soon, you may be surprised to find yourself with a rate of as low as 3.5%, McBride says. That s because these ARMs are typically pegged to the 12-month average of the one-year Treasury bill, which these days is well below 1%. (We re not talking about the subprime options ARMs here, whose rates are still prohibitively high for most homeowners.)

In this case, your decision to refinance hinges on how long you plan to stay in your home. If you aren t going anywhere in the next five or six years and the slightly higher payments with a 30-year fixed mortgage won t leave a dent in your budget, refinancing may still be a prudent decision for the long term. When the economy recovers and inflation becomes an issue, the prospect is that rates will become substantially higher, McBride says. You don t want to be sitting on an ARM when that day comes.

Lock-in periods

If you re offered a rate that s significantly lower than everyone else s, there s usually a catch. We all get our money from the same place, Sullivan says. Every conventional, conforming loan today is being written to Fannie and Freddie standards. Often, these lower rates come with shorter lock-in periods, sometimes as short as 21 days. Given the expected surge in applications, it may take well over four or five weeks to close on a loan. It s critical for people to understand how long it will take for the loan to be processed and make sure the rate lock is longer, Sullivan says.