I'm surprised no one has suggested that you recheck the dryness of your wood. My first year with an insert was very disappointing, all because of my wood not being dry enough. Got a moisture meter? Like IR thermometers, they're cheap now. Got a woodburning neighbor who's fanatic about burning dry wood? (Everyone here fits that description and you will too, very soon.) Get him to spot you an armful of really good dry stuff and see what happens. You may be pleasantly surprised.
I've been watching a few moisture meters on eBay just haven't pulled the trigger yet. I think this is a good enough reason to get one.