I'm trying to build a heat treating oven/kiln and I'm having a difficult time identifying equations to assist in sizing and insulation. I have info on sizing a heating element based on available power and I have and equation to quantify heat transfer through the walls and insulation but I'm having a hard time finding equations that i can use to estimate time to heat and object in the oven with available power and insulation. I need to be able to change variables (insulation, heating element, chamber size etc. ) in a equation (or equations) so i can have the best design possible before I start purchasing materials. Thanks in advance for any help.