How to use the Solar ROI Analysis
The Formula
Year-1 kWh declines by your degradation % each year. Savings blend self-consumed kWh at retail with exports at your net-metering rate—both escalating with inflation. Break-even is when cumulative savings repay net install cost after incentives.
Practical Example
Simple NPV discounts annual savings at your inflation %. The chart compares net solar savings (green) with cumulative grid spend if you never installed (dashed)—crossing zero marks payback.