A large globe light, like around a vanity mirror, that is rated at 25 watts consumes exactly the same amount of energy as a small refrigerator light bulb also rated at 25 watts..  Size as a power ratingThe wattage rating of a light bulb is directly proportional to energy consumed by that light bulb. A light bulb rated at 60 watts consumes 50% more energy than a 40 watt light bulb.