First, most solar water heaters on the market are not equipped with automatic display and control instruments for water temperature and water level, so the temperature is uncontrollable. Although it is equipped with electric heating auxiliary device, it is not automatic. When using hot water, the water temperature and water consumption are unknown, which brings a lot of inconvenience. Especially when the sun is weak in winter, you can't start the electric heater in time, and you have to wait for a few hours to take a bath.
Second, there is a fully functional solar water heater controller on the market, which can display the water temperature and water level, control the water level, automatically add water, give an alarm when water is short or full, and control the electric heater to automatically heat in time, which is very convenient to use.