[usconservative]

Correction: Also would need alot more panels if including the A/C, thereby also driving the cost up and the payback out further ...

[palmer]

I think you are correct for assuming summer use is better, but the panels are still only going to produce maybe 25% of their rated power in the summer.

So being optimistic, taking a $1 panel that is rated for 1W, you get 1kWh per 4000 hours (1000 is 25% of 4000). So in a little less than 1/2 of a year you get 14 cents worth of electricity from that $1 investment for one sunny season.