From a pure energy consumption standpoint, it cost you a lot more to heat that hot dog on the stove than it did in the microwave. The stovetop has a large resistive heating element that was on for five minutes. The microwave, even if it used more energy (and it doesn't), was only on for 30 sec. Now look at the circuit breakers in your main panel that these appliances are connected to. The oven/range is on a 40, 50 or 60 amp double pole (240 volt) breaker because it needs that much power. It may be the lagest energy load in your house when it is on. The microwave is on a basic 15 or 20 amp single pole (120 volt) household circuit. That's all the power it needs, and for a much shorter period of time.