Tankless water heaters, also known as demand-type or instantaneous water heaters, provide hot water only when it is needed. Unlike traditional storage water heaters, they do not incur standby energy losses, which can save you money. Typically, tankless water heaters deliver hot water at a rate of 2 to 5 gallons (7.6 to 15.2 liters) per minute. The growing demand for energy-efficient products...