The first point is that for solar water heaters, I personally recommend that you use solar water heaters with electric heater. Because the solar water heater is greatly affected by weather conditions, if the sun is not good, the water temperature may not be used, so it is recommended that you install an electric heater.
The second point is to once again recommend that everyone must do a good job of thermal insulation of solar water heaters. After the solar water heater is well insulated, it will save a lot of energy, and the water we release does not need to release so much cold water. The most important thing is to prevent the water pipes from freezing in winter.