Make sure that your replacement lamp works with your heater. You must choose the proper length, as well as the proper voltage, wattage, and color finish. King Electric offers 20-inch, 21-inch, 30-inch, and 43-inch replacement lamps, while voltage options include 120V, 208V, 240V, 480V, and 575V. You can choose 1600W, 2500W, 3650W, and 3800W lamps, while color finishes come in two options: clear and ruby.