K^2: Uhuh, so let's take the heater as an example. It will constantly use power to heat up (1000W for example when it's rated for it), and then, when the element is hot enough, it will turn off and basically use 0W, but it will turn on say every 10min to keep the element hot.
Integral: Ok, that is interesting and it does make a lot of sense. I actually had a theory about that. :)