The energy saving potential of tankless water heaters has ledmany consumers to consider replacing their storage tank waterheaters with tankless models. Tankless water heaters only heatwater when it is needed. The U.S. Department of Energy estimates atankless heater can reduce water heating costs by up to 30percent.The small size of the tankless heaters is also attractive wherethere is limited space. And, although there may be some maintenancecosts, tankless heaters should last longer than storage tank waterheaters.However, the initial cost of a tankless water heater issignificantly higher than the price of a new storage water heater.Forty to fifty gallon standard storage water heaters cost from $300to $650 at a major home store. The same store sells a 7.4 gallonper minute tankless water he