I cooked 8 pizzas on Saturday, July 13 at about 7:30PM. I burned the oven for about an hour and a half before that, less than 2 cuft of wood, and kept the coals and flames going while I cooked for another hour. Today at about 7:30PM, I shot the oven with my gun at 130+ degrees. That is 5 days with 6 inches of rain and about an 85 degree average ambient temperature. You can never have too much insulation.