The threads on this were several years old, so I want to ask again. Does anyone have experience with the "tankless" hot water heater. Our old electric unit is starting to leak, so it won't be long until I am out shopping. We have a 50 gallon unit now that keeps up with the two of us, but is strained when the kids come home.

While we are on it, is there any merit in having heaters in a series so that one works most of the time and the other is there for company?