Insulated Furnace
The insulated furnace is a highly efficient furnace. It can process three stacks of items at a time for only 2 stacks worth of fuel. (This is adjustable in the config by changing insulatedFurnace.heatPerBurnTick in the balance section of the config file)
The interface has 6 slots. The upper three are input slots, the lower three are outputs. The bar in the side shows how much heat is stored in the furnace.