Firstly,If the solar water heater in the bath water runs out, but people still do not rinse, then you can for a few minutes in cold water, hot water using the principle of cold water sink floating, the vacuum in the top of the water, you can then take a bath. Secondly,weather Forecast decide on the amount of water. If the next sunny day, the water can be filled; if the next day cloudy or cloudy, the upper half tank of water; if the next day there is rain, the water does not retain the original cold water. Thirdly,After bath in the evening, if there is a hot water heater tank nearly half of 70 ℃, in order to prevent excessive heat loss (the water is lesser, and the speed of the heat loss is faster), but also according to the weather forecast the decision of water; the next day sunny, then filled with water on; rainy days, the upper two-thirds of the water. Fourthly,it should also be considered in the purchase of the home resident population, in order to determine the purchase of household solar water heater capacity. Usually 40 liters of water per person standard is appropriate.