When it comes to finding the best deal on mortgage rates, some homeowners might be feeling as if they missed the boat.

Earlier this month, interest rates on 30-year fixed-rate mortgages hit their lowest point since the spring, falling to 4.89 percent. Plenty of homeowners rushed to take advantage of those cheap rates with mortgage applications climbing 18.2% week over week, according to the Mortgage Bankers Association. But last week rates were on the rise again. Last Friday, the rate on the average 30-year mortgage hit 5.32%, according to BankRate.com.

Those who failed to lock in those sub-five percent rates are now faced with a quandary: Refinance now before rates rise even further or wait for rates to start falling again.
With the Federal Reserve making noises about winding down its monetary stimulus, the odds that rates will fall below 5 percent again are shrinking fast. Waiting for a better rate could mean missing out on today's relatively low ones. Keep in mind that rates are still significantly lower now than they were just last September when the average 30-year fixed rate mortgage charged 6.5%.

Ultimately, your decision should be based on the type of loan you have and the rate you're paying. Those who have an adjustable-rate mortgage or a home loan with a balloon payment, for example, may want to lock in a fixed-rate mortgage now before the Fed starts goosing rates higher. Meanwhile, those who have a 30-year mortgage carrying a fixed rate of 6 percent or higher may discover that, even after accounting for refinancing fees, they can still save plenty by refinancing now.

To determine whether it makes sense for you to refinance, calculate what your mortgage payment would be for a 30-year mortgage using today's rates versus what you're currently paying. Then find out what the average costs are to refinance in your area. Lending Tree is a good source to get mortgage lenders bidding for your loan. After filing out an application, you'll get bids from about five lenders. By getting bids from several sources, you can generally start pitting one lender against another and get an even lower-cost offer.

Say you have a 30-year mortgage of $200,000. If you were lucky enough to lock in at the most recent low of 4.89 percent, your monthly principal and interest payments would amount to $1,060.24. If you waited and refinance at the current rate of 5.32 percent, however, that payment would be $1,113.09, or $52.85 more per month. But say your existing loan carries a rate of 6.32 percent, just one percent higher than the recent 5.32 percent rate. If you don't refinance, your payments would be $1,240.55, or $127.46 more per month than you'd pay at the 5.32 percent rate. Should you land a low-cost refinancing deal and lock in the 5.32 percent rate, you'll likely recoup whatever you pay in out-of-pocket refinancing fees within two years. After that, the remaining savings is all yours.

Just how much is that savings over 30 years? According to amortization charts using a mortgage calculator at BankRate.com, the cost differences among these loans over 30 years are dramatic. The 4.89 percent mortgage would result in total interest costs of $181,685.73. The 5.32 percent mortgage, would cost $200,714.06, and the 6.32 percent loan, would cost $246,599.50. So if you're determined to stay in that home for 30 years, you can save almost $46,000 over the life of the loan by cutting your interest rate by just one percent.

If you can lower your interest rate by at least one percent or lock in a fixed-rate, definitely consider a refinance. Just keep in mind that the process can take 30 to 45 days or more to complete and, in that time, interest rates may fluctuate. If you want to bet that rates will go down then you don't have to lock in a rate at the time of application. You can lock in your rates any time during the mortgage underwriting process. If you think the rates will go up, then lock your rate when you file an application to secure the rate you like.

Lita Epstein has written more than 25 books including The 250 Questions You Should Ask About Buying Foreclosures."