Who told you the math behind this? It won’t be two years. You’ll be lucky to get a 20 year return.”
You would have to get a huge tax credit or some other way that somebody else is paying for it then.
Solar is very expensive and very long payback if at all; from all I have seen.
Combined federal and State solar credits are about 50% of the cost. So a 5kw system at $25,000 would get about a $12,000 tax credit, leaving about $13,000 to pay.