Do kilns fire cooler on the bottom?

Kilns tend to fire cooler on the bottom, but not because heat rises. The movement of heat through convection ends at around 1100 degrees F. At 1700 F, a cubic foot of air has only about one-tenth the number of molecules as at room temperature. This is why there is little airflow in an electric kiln at high temperatures. The bottom and top tend to stay cooler because the brick bottom and lid are large thermal masses that absorb energy. Paragon compensates for this by making the bottom and top elements fire hotter than the center elements. You can improve heat distribution inside the kiln by loading less ware in a cool section and more ware in a hot section. Slowing the firing also helps.