Residential payoff takes a lot longer unless your roof, weather, and/or local electric regulations are really good, especially now that interest rates went up. Most are paying 4 cents per watt financed at at 3%+.

I got in at .99% and it still wouldn't be obviously worth it in terms of ROI if not for the tax refund. A big cash infusion when the market is low like this could tangibly impract retirement age. But without it, especially with interest rates as they are now I could see people taking longer than the 20-25 year life of their loan to net positive.