With people’s increasing awareness of environmental protection, renewable resources became very popular, thus experts and scientists in the field of energy also pay more attention to how to take full use of renewable resources. Solar energy is a well-known renewable resource. And now the most famous invention which adapted the solar energy technology is the solar water heater. Recently the solar water heater is widely used in most Chinese families for heating water. This kind of water heater has the advantages of being clean, safe, and cheap. It helps us improve the living standard.