Compare type of water heater control

Type of control	Hot water always ready	Hot water ready based on your program	Hot water when you turn on timer	Pay to heat water continuously	Control how much you pay	Continuous build-up of calcium carbonate in tank	Low calcium carbonate	Life of water heater
No control: Water heater always on	x	0	0	x	0	x	0	normal
All Programmable timers	0	x	0	0	x	0	x	extended
All Countdown timers and ordinary switches	0	0	x	0	x	0	x	extended

A timer means	Fewer replacements	Less chemical build-up	More money in your pocket

For other useful charts and information, see Do-it-yourself