With home loan rates at historic lows, many people are rushing to refinance. But, before you fill out the paperwork, lenders say you need to do your homework.

Lenders say refinancing your home can save you big bucks on your monthly payment – if you wait for the right rate.

Homeowners Rudy and Renee Carlson are about to refinance their home for a third time – a decision driver by these low rates.

"Right now I've seen the rates from 4.25 to 4.5 and that is pretty much right in the zone as far as what we're looking at,” Renee said.

"We're seeing a great rush to refinance with rates being as low as they are,” added Mark Willer, with Royal Credit Union in Eau Claire. “Our volume has tripled since November and currently we've got about 1,000 applications pending. Our people are working 10 to 12 hour days just to keep up with the volume."

So, just how much money could these low rates save you? RCU Home Loan Representative Lisa Stelter put together this example:

Say you’ve got a 30-year fixed-rate loan for $200,000. At today’s rate of 5.09% -- your monthly payment would be $1,084.67. Compare that to 10 years ago [1999] when the rate was 6.79% -- making the payments $1,302.52 a month – and 20 years ago [1989] when the rate was 10.73% -- making the payments $1,863.96 a month.

"Typically the rule of thumb is that if the interest rate spread is more than a percent over what you're currently paying -- it’s worth considering refinancing,” Willer said.

But, don’t forget about the closing costs, an amount Stelter says now depends on your credit score.

"You want to weigh the benefit of paying for the cost of refinancing vs. how long you are going to be in the house,” Willer said. “If you only plan on being in the house for another 2 to 3 years, it probably doesn't make sense to try and refinance at today's rates."

According to Freddie Mac, the highest interest rate for a 30-year fixed-rate mortgage since 1971 was 18.45% in October of 1981.