See when your system pays for itself and what it earns you over 25 years, accounting for rising electricity prices and panel degradation.
Model assumes savings grow with your rate escalation and shrink with panel degradation each year — not a flat multiplication.
Further reading: Cash vs. Loan vs. Lease vs. PPA: Which Solar Financing Actually Wins?
Two assumptions drive most of the disagreement between solar ROI calculators: how fast electricity prices rise, and how much panels degrade. We default to 3% annual rate escalation (roughly the long-run average in mature grids) and 0.5% yearly output loss (typical for a modern monocrystalline panel with a 25-year warranty), but both are yours to change.
No — this models a cash purchase. If you're financing, use the Solar Loan Calculator alongside this one to compare your loan payment against the monthly savings shown here.
Installer quotes sometimes assume optimistic sun hours, no degradation, or higher-than-typical rate escalation. Try their production estimate in the sun-hours field to compare apples to apples.