So: It is a saving compared to Eskom/City Power etc who continally put up the price. You would have to calculate what it is over the 25 plus lifespan of your system. A solar system is not an investment but really a prepayment for power with a guarantee that you have a continued supply. At my home if it is sunny I can even run a pool heat pump but it won't cover winter and underfloor. Have I saved considerably? Yes, but now the 500 a month I would use (say to cover the pool heat pump) has nearly doubled so I'll look to add more panels (or just leave the heat pump off).