The short answer is yes, the longer answer depends on your appraised value. Obviously you won't know your appraised value until you dip your toe in the water, but it's probably worth. You should (based on current rates) be able to save a minimum of .625% possibly up to 1% without paying any points on a refinance assuming you are at or below 80% LTV. I would assume that this is the case, if so you can plan on saving about $2800 in interest per year on the loan. Closing costs vary regionally especially if you have to pay any sort of tax stamps etc, but regardless you should be able to more than recoup your cost inside of the 5 year period. Ultimately, talk to a loan officer or two and feel out the situation. Once you have a rate and cost quote, decipher how much interest you will save per year/month/etc and weigh that versus the cost of refinancing.
If for example you would save $2800 in year 1, and it would cost $3600 to refinance, it's well worth it if you plan on being in the home 5 or more years. You would have recouped cost in the first 15-16 months and from that point on you would be ahead of the game.
AC