I insulated my WSM with foil backed insulation. It looks like a space ship now but boy it really holds the heat. The challenge now is to keep the temp low enough without choking it off. I runs with just one vent BARELY cracked. Anyway, it ran for 15 hrs. the other day and when I took the butt out I shut the top vent. Next day I checked to see how much charcoal was left and was amazed that there was over 1/3 left. Awesome. I should have put a chunk of apple in though. I didn't because I like the brisket with no additional wood. I am running Royal Oak lump and it seems good as it is. Maybe just a smaller piece of wood. I used the leftover charcoal this morning to smoke some jalapenos it is running great, as usual.