It’s not always a clear answer. How long you plan to stay in the house is one of the factors. Here is a good article that shows how a refi would work.
There are useful links in the article to calculators to help you find your answer. You can also find the latest refi rates at bankrate for your state. I’ve used bankrate many times over the years to save us money and I trust their information. (I have no affilifation with them.)
With interest rates probably on the rise due to the US credit rating downgrade, it’s worth your time to run the numbers.
Click the title of this post to link to bankrate.