They will put insulation around areas so cold air does not come in. Put a cap on the top of the chimney. Our guy wanted to take insulation out of the garage. I said no, so he had to get some at home depot.
There has to be someone around that specializes in this-that is not Lowes, HD, etc.
Mine was a Heat-n-Glo. Here is the website for the retail company in Maple Grove, MN
http://www.fireside.com/browse/inserts