Charlotte:–Most electric water heaters are warranted for a period of 5 years against tank failure (leaks). Most electric water heaters are very similar in the thermal efficiency, and the insulation R value. The purchase price is primarily the determining factor of cost effectiveness. Heater A. cost$300 and lasts 5 yrs.= $60 per yearHeater B. cost$450 and lasts 5 yrs.= $90 per yearHeater A. is the most efficient, given that the operating cost is identical for both heaters. Careful shopping can save a substantial amount of money over the life of the heater. Lots of luck….Bud