I may not be the expert, but I do have a demand hot water heater that does indeed enable me to take arbitrary length showers. Mine's LPG powered, as it uses 117Kbtu/h at full tilt, which is, of course, a little over 34KW. There are electric demand water heaters, but they're mostly designed for remote sink use, and don't support much flow rate. And the laws of physics dictate that, even with a 240V feed, you'd need over 100 amps to deliver that kind of power electrically. No wonder gas units are popular. Even with current prices, electricity is an expensive source of heat.
(no subject)
indeed enable me to take arbitrary length showers. Mine's LPG powered,
as it uses 117Kbtu/h at full tilt, which is, of course, a little over 34KW.
There are electric demand water heaters, but they're mostly designed for
remote sink use, and don't support much flow rate. And the laws of
physics dictate that, even with a 240V feed, you'd need over 100 amps
to deliver that kind of power electrically. No wonder gas units are popular.
Even with current prices, electricity is an expensive source of heat.