Installed solar this spring. Took out two loans (1 y/r 5%, and 15 y/r 4.5%), with full intention of paying off early.
Just paid off the 1 y/r loan 9 months early, saving almost $1000 in interest.
As soon as state SREC check clears, and we capture 30% tax credit early next year, we will pay off the 15 year loan, 14 years early, saving... a lot.
Our friends think we're crazy. I'd like to think you all understand my joy. :)