Mortgage rates are lower than ever this year, making refinancing a must for many homeowners. You can trade in your old loan for a new one that might easily chop hundreds of dollars off your monthly mortgage payment.

A 30-year fixed-rate mortgage may be the borrower's go-to loan for a refinance. But if you've been in your house a few years, refinancing to a 15-year mortgage can help you avoid dragging out the debt and piling up massive lifetime interest.

The monthly payments on a 15-year home loan can be stiffer, but the interest rates are lower — currently averaging an all-time-low 2.26%, nearly one-half of one percentage point less than the typical 30-year mortgage rate, according to mortgage company Freddie Mac.

Here are five tips on how you can get the very best deal when refinancing into a 15-year mortgage.

1. Do the math on 30- and 15-year loans

Most mortgage lenders offer both 30- and 15-year terms. Compare the current average rates between the two loan products, then focus on a couple of lenders and see how their 30- and 15-year rates differ.

If 15-year mortgage rates don't seem substantially lower, it may not seem worthwhile to accept the steeper monthly payment that comes with the shorter-term loan.

Still, the long-term savings can be considerable.

says rates are now averaging 2.71% for a 30-year fixed-rate mortgage, versus 2.26% for the 15-year option. Let's say you're trying to decide whether to refinance a $200,000 mortgage balance for either 15 or 30 years, at today's average rates.

• Your monthly payment (principal plus interest) would be $1,311 with a 15-year mortgage at 2.26%, yet only $812 with a 30-year loan at 2.71%.

• But you'd pay total interest of about $36,000 with the shorter-term loan, versus roughly $92,450 — $56,450 more — over the course of the 30-year mortgage.

2. Be the best borrower you can be

Before you start applying for mortgages, check your credit score. These days, it's very easy to take a peek at your score for free.

A lender wants to feel confident you'll pay back the loan and not default — particularly at a time when so many people are in a financial squeeze from the coronavirus pandemic. A very good (740 to 799) or excellent (800 or higher) credit score will help provide that assurance.

If your score could stand improvement, request copies of your credit reports from the three major credit reporting bureaus — Equifax, TransUnion and Experian — and make sure they're accurate.

Bad information, such as debts that aren't yours, or debts that are too old and should have fallen off the reports, can weigh down your credit score.