... the hard water. 4) Saving water, automatic control, no need preheating, no need wait for. Advantages: A) Save water: Ordinary storage water ... electricity: This product USES real terminal heating mode, no preheating, no heat preservation, no pipe heat loss; However, by using Ordinary storage ... 15%. C) Save worry: 24 hours a day, no need to worry for without hot water; Just One action, instant hot ...