[BeanAnimal]

pwest, I think you need to rethink your answer. Your definition of efficiency only applies to the fact that the fan moves more air than the light bulb (if you are talking about fans). In terms of heating efficiency the lightbulb would be more efficienct. In terms of motion efficiency, the fan wins. In terms of light output, the bulb wins. A lightbulb is not an efficient motor, and a motor is not an efficient lightbulb. Though, the motor does create motion AND electromagnetic radiation.

This is basic physics at it's best.

Lock any two devices that consumes the same amount of POWER into a sealed box. Both will heat the box at the same rate, regardless of their "efficiency".

An incandescent bulb may heat the water in the tank faster than a fluorescent bulb because it radiates more heat in the infrared spectrum. Make no mistake, if both bulbs consume the same amount of power, they radiate the same amount of heat.

The motion of the fan is a form of energy. Energy is heat. The fan blades move air, and that air is energy.

Honestly... I don't want to get bogged down on this. I think if you do some research and think back to your physics eduacation you will arrive at the correct answer.

Lets also not get REAL POWER and REACTIVE POWER and the power factor messed up in this. For our purposes here those are simply a means of expressing they way we use generated power and are billed for it. We are talking the sum total of the power consumed (in watts in this case).