It seems we struck a nerve with a couple of recent columns about on-demand water heaters. Also known as tankless water heaters, on-demand heaters deliver an almost-never-ending supply of hot water if properly sized and installed.
Our first column on the subject responded to a reader who wondered whether replacing a conventional water heater with a tankless model was a smart move. We said that conceptually that was a reasonable way to go. Heat only the water you use, rather than heating, storing and then reheating when needed. It makes perfect sense — we thought.