The water heater we made is a smart and tankless type. Once water is going inside and running through this water heater from the inlet to outlet, then the water heater starts working. If no water going inside / running through, then it will automatically stop working.There is LED temperature display. Temperature can be easily touched and controlled. These smart water heaters can automatically heat water with different powers according to different cold water temperature. It works with full power based on cold water in the winter, but works with smaller power in the summer. That helps us save electricity. It takes 3 ~ 5 seconds for creating endless hot water. No need to preheat water and wait for washing / shower, and no need to re-heat a tank of water again when it become cold (concerning storage type). That will help us save electricity also. Only working status costs electricity. Multiple safety protection is matched with this product such like overheat protection, electric leaking protection, prevention of heating up without water.