Re:bad science = scam (Score 2, Insightful)

OK, I'll buy the first part, you can't heat water quickly enough for on-demand use such as a shower, as it would require unreasonably high current, even if the electric water heater was 100% efficent. I've done the math on that.

You must be really bad at math, because I had a shower one hour ago using the on demand electrical heater that's been in my apartment for some 15 years. And it was set to "1", because the water is too hot to shower with on the "2" setting.