We have a heatilator EC-42 fireplace and from reading here I see that there are some inserts that will fit. We called the installer that the dealer recommended and he was here yesterday. He told us that to put a bigger insert into our fireplace he could take out all the refractory panels and basically "gut" the firebox and that it was perfectly safe to do so (just leaving the metal firebox). Everything I'm reading says NO, the refractory panels have to stay in place and there are only a few things that can be safely removed. He said there are all these air chambers on the insert that will make it safe to remove the refractory panels because the outside of the unit won't be that hot. I had already found an insert that was pretty big that would fit without taking these out so I don't know what the big deal is but he was pretty insistent that they can all safely come out. My husband said he doesn't think it's a good idea either but thinks what this guy said "makes sense". I'm totally against it, I want it installed exactly like the installation instructions say to install it. So, is this guy correct and it IS safe to remove these things? We can't find much online on this. thanks!