Hello all! I am recently started on a 275 gallon RFS build, but have some questions concerning maximizing efficiency in the firebox (which I have yet to fabricate). I was wondering if anyone has tried insulating their firebox, and if so, did it increase burn time? I am planning on over sizing my firebox and adding fire brick inside it in hopes of increasing heat transfer to the cook chamber and hopefully conserve charcoal in the process. I would greatly appreciate any input on any pros/cons on doing this.