Not trying to shoot holes in this, but you will have to stay in the home for the 20 years. If you sold the home in 10 years, you would be paying the new home buyers power bill for the life of the original system. Don't know if the warranty is transferable, but if it is, I would want to recuperate some of my initial investment. That means the new buyers would have to be educated enough to see the value. Hmmmm.