Solar planning · United States
Solar sizing for Phoenix
Use 5.7 peak sun hours per day as a rounded first-pass value for Phoenix. A 5 kW array with 20% losses would produce about 22.8 kWh on an average planning day.
Calculate your array
Enter 5.7 in the solar system size calculator, then add your daily use, roof area, orientation, and shading. Rounded peak-sun-hour planning values from Global Solar Atlas; verify a roof design with site-specific irradiance and shading. Global Solar Atlas.
How to use Phoenix sun hours
A 5 kW array at 5.7 peak sun hours and 20% losses produces about 22.8 kWh on an average planning day. Multiply your daily demand by 1.25, then divide by 5.7 to get a first-pass DC size. Monsoon, shading, roof direction, and temperature can move the real result substantially.
Questions to check before buying
- Is the roof free of shade during the strongest solar hours?
- Does the installer use a monthly or seasonal production model?
- Are export limits, battery losses, and local approval rules included?