Payoff is definitely dependent on your usage. We live semi-coastal – so no AC in the summer – our latest sdg&e bill is $47 for a 2000sf home. And a portion of that was gas for cooking.

We’ve crunched the numbers and our payoff – assuming we could get all the rebates – is about 12 years with current usage. We’re holding off for 2 things:
1) we’ll consider after we replace our roof… Roof is 14 years old and we don’t want to have to take down/reinstall the panels when we redo the roof in 15 years.
2) if we get a plug in electric car – we’ll look at it because our usage would justify it then.

Our neighbors, same house, but higher usage, have an 8 year payoff. They got them a few years ago and love watching the dial spin backwards.