Estimated payoff is between 10-15 years. This is significantly better than it was 5 years ago, so I'm happy. But the CEC rebates are going down each year, and silicon is getting more expensive, so this seemed to be the best time to buy. And frankly, the only time I've had the money for this kind of thing in recent years.
But that's the end of my budget. So much for fixing my bathroom or kitchen - those projects are now on hold until this is done and I can save up some extra money.