If you know that you will be moving in 3 to 5 years, you might want to consider refinancing to a 3 or 5 year ARM (adjustable rate mortgage). These loans typically have a much lower rate that a traditional fixed rate loan such as a 30 year fixed, but they do have a fixed rate for the first 3 or 5 years of the loan. This will enable you to benefit from the lower rate, but you won't ever have to worry about the risk of a rate adjustment because you will be selling the home before the fixed-rate period ends.
The majority of your mortgage payment goes toward paying interest. To save an astounding amount of money over the long term, choose a mortgage loan with a lower rate and a shorter payback term. A 15-year mortgage may be just what the financial planner ordered. This type of loan carries a larger monthly payment; but if your budget can withstand the jolt, you can save big bucks over the long haul.
Give yourself plenty of time to close. With most refinancings, your file is turned over to a closing or title company, which dictates the closing details. Like the lenders themselves, these firms are swamped when interest rates are low. Moreover, appraisers get backed up and can be difficult to schedule. So don't expect the closing to happen as quickly as anyone promises.
Weigh the costs carefully of how long you will be staying in your home vs. how much of a savings you will be getting in a refinance. Make sure you include closing costs in your decision.