How to Estimate Solar Power Revenue
Monthly solar generation is calculated as: system size (kW) × peak sun hours per day × 30 days × system efficiency (%). Peak sun hours represent the average daily solar irradiance and vary from about 3.5 h/day in the Pacific Northwest to 5.5 h/day in the Southwest. System efficiency (typically 75–85%) accounts for inverter losses, temperature effects, and panel degradation.
The default grid sale rate of $0.08/kWh is an approximate net metering value for excess solar energy fed back to the grid. With net metering, you may effectively earn your retail electricity rate (typically $0.10–$0.20/kWh). The actual rate depends on your state, utility, and current net metering policy.
This calculator is a planning tool. Actual output depends on roof orientation, tilt angle, shading, and weather. For investment decisions, get quotes from certified solar installers who can model your specific site.
Frequently Asked Questions
Monthly kWh = system size × peak sun hours/day × 30 × efficiency (%). Peak sun hours vary from ~3.5h (Pacific Northwest) to ~5.5h (Southwest).
With net metering, use your retail electricity rate (typically $0.10–$0.20/kWh). The default $0.08/kWh represents a conservative feed-in tariff estimate.
For a 6 kW system (~$15,000 after federal tax credit), payback is typically 6–12 years depending on local rates and incentives.