The ROI (return on investment) of systems can vary based on multiple factors. Typically, the larger the system, the greater the savings and the faster the ROI. While individual results vary, PV systems typically have a 10-15 year ROI and thermal systems are about 5-10 years. Solar attic fans and solar pool heating systems typically have a 3 year ROI. It may be more useful to think of solar as an investment that yields an annual return, much as a bank savings account that provides interest. A solar system will generate savings that can equal a bank account generating a twenty percent (20%) annual return, and the savings are not taxed as income, as is the interest you earn at the bank. The truth is, if you want energy, you will be paying for it. You may prefer to pay the utility bill forever, or you may wish instead to go solar, and become your own utility. It is quite similar to the reason you once decided to buy your home and stop renting. Solar is simply the best investment available today because it guarantees a return on money that you will otherwise “burn” and helps you develop equity as you bank your savings.