I've been using an old refrigerator for a year now and it works great. it's to small when it comes time for our rib feed and when we make our family sausage recipe. My father inlaw has a new spear house that was given to him and is to heavy for three guys to move on the ice. It has 2x4 walls and ceiling and is sprayed with polyeurathane insulation. I can keep the ins cool with no problems and seal it from the cooking space. But will it hold to much heat? It is 6'tx6'dx5'w