Your household's yearly electricity usage in kilowatt-hours (kWh)
Total capacity of your solar panel system in kilowatts (kW)
Average peak sun hours per day in your location (typically 3-6 hours)
Your average cost per kilowatt-hour
Expected annual increase in electricity rates (typically 2-4%)
Complete cost of solar panel system installation
Available federal tax credit (currently 30% in the US)
Expected annual loss in system efficiency (typically 0.5-0.8%)
Number of years to calculate savings and ROI