Refinancing a mortgage means paying off an existing loan and replacing it with a new one. There are many reasons why homeowners refinance: the opportunity to obtain a lower interest rate; the chance to shorten the term of their mortgage; the desire to convert from an adjustable-rate mortgage (ARM) to a fixed-rate mortgage, or vice versa; the opportunity to tap a home's equity in order to finance a large purchase; and the desire to consolidate debt.

Securing a Lower Interest Rate

One of the best reasons to refinance is to lower the interest rate on your existing loan. Reducing your interest rate not only helps you save money, it also increases the rate at which you build equity in your home, and it can decrease the size of your monthly payment. For example, a 30-year fixed-rate mortgage with an interest rate of 9% on a $100,000 home has a principal and interest payment of $804.62. That same loan at 4.5% reduces your payment to $506.69. 

Shortening the Loan's Term

When interest rates fall, homeowners often have the opportunity to refinance an existing loan for another loan that, without much change in the monthly payment, has a significantly shorter term. For that 30-year fixed-rate mortgage on a $100,000 home, refinancing from 9.0% to $5.5% can let you cut the term in half to 15 years, with only a slight change in the monthly payment from $804.62 to $817.08.

Converting Between Adjustable-Rate and Fixed-Rate Mortgages

While ARMs often start out offering lower rates than fixed-rate mortgages, periodic adjustments can result in rate increases that are higher than the rate available through a fixed-rate mortgage. When this occurs, converting to a fixed-rate mortgage results in a lower interest rate and eliminates concern over future interest-rate hikes.

Conversely, converting from a fixed-rate loan to an ARM can be a sound financial strategy in a falling-interest-rate environment. If rates continue to fall, the periodic rate adjustments on an ARM result in decreasing rates and smaller monthly mortgage payments, eliminating the need to refinance every time rates drop.With mortgage interest rates rising, on the other hand, as they have begun to do, this would be an unwise strategy.

Tapping Equity and Consolidating Debt

Homeowners often access the equity in their homes to cover major expenses, such as the costs of home remodeling or a child's college education. These homeowners may justify such refinancing by pointing out that remodeling adds value to the home or that the interest rate on the mortgage loan is less than the rate on money borrowed from another source. Another justification is that the interest on mortgages is tax deductible (although the 2017 tax law has reined this in for both existing and new mortgages).