In New Jersey Refinance Rate a fixed-rate mortgage is a loan that features a constant interest rate for the life of the loan term. When you take up this form of mortgage, you should be aware that while your payments will remain constant, there may be some factors that cause your monthly income to fluctuate from year to year. The price of your escrow plans, such as the cost of insurance and property taxes, may change even though your house will be paid off and your interest rate won't change.