Solar ROI (Return on Investment) is the percentage return generated by a solar installation, calculated as annual savings divided by total system cost, expressed as an annual percentage. ROI measures the annual financial benefit as a percentage of capital invested.
ROI Calculation
ROI equals annual electricity savings divided by total installed cost, multiplied by 100. A $20,000 system generating $2,400 annual savings produces 12 percent annual ROI. This calculation typically excludes tax credits and financing benefits, which are often evaluated separately. Multi-year cumulative ROI compounds these returns, showing exponential wealth building over system lifespan.
Performance Variables
ROI varies significantly based on electricity rates, system efficiency, sunlight exposure, and financing method. California systems average 8 to 12 percent annual ROI, while Hawaii and Massachusetts exceed 15 percent due to high electricity rates. Loan financing typically reduces ROI by 1 to 3 percentage points compared to cash purchases due to interest costs.
Comparative Analysis
Solar ROI typically exceeds 7 to 10 percent, competing favorably with stock market returns averaging 10 percent historically. Tax-credit-adjusted ROI often reaches 15 to 20 percent in the first year. Investors compare solar ROI against alternative investments, making it a critical metric for financing decisions and long-term wealth planning.