Yes... electrical on demand water heaters do generally require 3 - 40amp circuit breakers. They are staged so that the second and third circuits only come into use when there is an "extreme" demand for hot water. My experience is that people for whom I have installed the electrical portion of the water heater are happy. The real key lies in how much hot water they use.... If its a one or two person home.... a standard hot water heater is probably more practical. If there are four or more people in the home, the on demand water heater makes sense. Consider this... if you have two people in the house... a 20 or 30 gallon heater is sufficient.. if you have a full family... mom, dand and a bunch of kids... demand will be much more frequent and they'll need a really large water heater... 50 gallons minimum... How much power does it take to heat 50 gallons non-stop? Dishes, showers, etc.