If you've already paid off quite a good percentage of your mortgage loan, and you finance for another 30-years (or longer!) loan, you may end up paying more interest in the end. It depends your current interest rate and the one you switch to when you refinance. If you're looking for maximum savings, you should refinance your home for a lower interest rate with a loan term that is equal to or less than the amount of time left on your current mortgage. If, for example, you only have 15 years left on your current mortgage, it's smartest to choose a refinance loan with a 15-year term.