The formula
A worked example
A 5 kW array × 4 peak sun hours × 30 days × 80% produces an illustrative 480 kWh for that period.
What this estimate includes
Peak sun hours are equivalent full-intensity sunlight hours, not daylight hours. This simplified model does not use your location or live weather. Use site-specific resource data; do not multiply a sunny summer month into an annual forecast.
Common questions
Is this a site-specific solar forecast?
No. This is a transparent arithmetic estimate. Tools such as PVWatts model location and system conditions in greater detail.
What belongs in the performance factor?
Use a combined assumption for conversion and other losses. Avoid subtracting the same loss twice. Shading, orientation, temperature and equipment choices matter.
Further reading
PVWatts: detailed site-specific solar modeling. Background reference; these tools are independent and are not endorsed by the source organization.