I have just been a part of some research on turning a house onto solar power with the idea that he would run his home on sufficient solar so as to roll the meter back during the day and suck off the grid at night, when his demand for power was much lower.

He knew what his annual kilowatt hrs were and he supplied that to the distributors that he was talking to when discussing his needs.

After looking at the estimates that he received, I advised him to do the math-money wise.

When he did that math, he found a curious coincidence. He has been consistently quoted a lifetime of 28 years for the solar panels. The prices quoted were consistently HALF of his projected electrical costs for 28 years. In other words, the price quoted is based, not on actual costs, but what the distributors calculate will be half of his regular cost, no matter what hrs he was quoting. IMHO, this sounds like trying to buy a used car.

This sales tactic is designed to fool people into paying a much higher profit margin that what is reasonable and is significantly slowing the spread of personal homes from becoming power sufficient.

Now do the math in this regard and see what you are finding. Another item of interest: I am being told by some that the true lifespan of solar panels is anywhere from 15-28 years!! That can seriously change the outcome of the money side of "doing the math"!!