Plan Ahead (For Replacement)
Don't wait until your existing water heater fails before you look into replacement. It often makes good economic sense to replace an old inefficient model with a high-efficiency one even before the old one fails. With storage water heaters, read the Energy Guide labels and buy an efficient model.

Life-Cycle Costs for Water Heaters
When you're choosing a water heater, don't be tempted to simply buy the lowest-cost model available. Water heating uses too much energy to make the decision lightly. The unit's initial cost is a small fraction of the money that will be spent operating it over its lifetime.