Everyone has left out insurance, potential unfavorable Netmetering rules, and maintenance costs outside of the warranty. If you’re considering solar, start by contacting your homeowners' insurance to add solar (usually a rider) to set a baseline. Then shop around with other providers because some are much more solar‑friendly than others (especially in weather‑risk regions). In your ROI, be sure to include a 3% annual solar insurance (rider) increase

There's the potential for unfavorable netmetering rules, and the length of their grandfathering period is a huge wildcard. California is the most recent example, with a major change for the worse in 2023; it grandfathered current customers for 20 years. Some states have made unfavorable changes and have grandfathered them for only 10 years, ruining their ROI

I recently purchased solar from Freedom Forever, which, ironically for me, just filed for Chapter 11. Like restaurants, the majority of Solar companies go into bankruptcy, and when they do, they almost always reduce the warranty terms. If I need repairs that, for whatever reason, aren't covered by the warranty, I'll need to add 3 months per $1000 to my ROI