A method of making a heater includes an aluminum nitride base having equal to or less than 1% impurities, particularly one embodiment having none of polybrominated biphenyl, polybrominated diphenyl ether, hexabromocyclododecane, polyvinyl chloride, chlorinated paraffin, phthalate, cadmium, hexavalent chromium, lead, and mercury. The base is fired in a heating unit before any layering. Thereafter, on a topside and backside of the base a conductor layer is layered and allowed to settle and dry before firing. Next, a resistive layer is layered on the base from a resistor paste such that the resistive layer connects to the conductor layer on the topside. The resistor paste is allowed to settle and dry and then the base with the conductor and resistor layers is fired. At least four layers of glass are layered next over the resistive layer, each instance thereof including layering a glass, drying the glass and firing.