1. If the water in the solar water heater runs out while taking a shower and the person has not washed it clean yet, you can apply cold water for a few minutes. Using the principle of cold water sinking and hot water rising, the water in the vacuum tube can be pushed out to continue taking a shower. 2. The weather forecast determines the amount of water to be poured, which can obtain a satisfactory water temperature. If it is sunny the next day, the water can be filled to the brim. If it is cloudy or cloudy, the upper half of the tank can be filled with water; If there is rain, keep the original water and do not use cold water. 3. After taking a shower at night, if there is still half of the hot water in the water heater tank at nearly 70 ℃, in order to prevent excessive heat loss (the less the amount of water, the faster the heat loss), the amount of water should also be determined according to the weather forecast; On a sunny day the next day, it will be filled with water; On rainy days, 2/3 of the water is added.