Peak sun hours by state (quick table)
Find typical peak sun hours by U.S. state and season, and use them in the panel sizing calculator.
Quick take
Use the table to pick a realistic PSH value for your location, then plug it into the sizing calculator.
How to use the calculator
- Open the calculator linked below.
- Enter the numbers that match your setup.
- Use our rules of thumb to sanity-check the result.
Rules of thumb
- Start with daily kWh ÷ peak sun hours.
- Apply a 15–25% derate for losses.
- Round up to the next standard panel size.