Every household uses different amounts of hot water.
How much you will save on your electricity bill by using solar hot water heating will depend on how you use the system, the size of your system and where you live. All have different interest rates and will give different rates of return. A Thermocell solar system has a payback of less than 8 years. After that, your summer hot water is free, as is a considerable amount of your winter hot water. When to Install 1.