The wattage of the heat bulb depends on the size of the enclosure, the species of reptile, and the temperature gradient needed. It's important to research the specific requirements of your reptile species and consult a reptile expert or vet for advice on the appropriate wattage. We also strongly recommend using a thermostat in conjunction with any heat source you have for your reptile. This ensures the heat source does not overheat, and stays at the temperature you have set.