Solar Output Estimator
Estimate potential solar energy output.
Solar Output Estimator
Enter system size, average peak sun hours for your location and a system loss factor. The estimator returns approximate daily, monthly and yearly energy production.
How the estimate works
Daily energy (kWh) = system size (kW) × peak sun hours × (1 − losses). A “peak sun hour” is one hour of 1,000 W/m² irradiance, so 4.5 peak sun hours is the same energy as 4.5 hours of full noon sun even though the actual daylight is much longer.
Choosing the inputs
- System size: the DC rating of the panels, for example 20 panels × 400 W = 8 kW.
- Peak sun hours: annual averages run from about 3 in the cloudy north to 6 in the desert southwest. Use monthly figures for seasonal estimates.
- Losses: 14 percent is a common default covering inverter efficiency, wiring, soiling, temperature and mismatch. Shaded roofs lose considerably more.
Verifying real output
An irradiance meter tells you how much sun is actually hitting the array, and a PV tester measures what the panels deliver under that light. Comparing the two exposes soiling, shading and failing panels. See the solar and renewable tools guides.