1) Conventional Tank:
Electrical: Consists of 2 elements, 2 thermostats (1 upper and 1 lower). Lower 50% of heater remains heated at all times. When demand for additional hot water is required, the upper element kicks in.
*It is estimated that 30% of your power bill is used to heat water in this manner.
2)Gas: Natural or propane gas tank type heaters keep the entire tank hot at all times.