Welcome to the updated PVWatts Calculator!



PVWatts now uses solar resource data from the latest NREL National Solar Radiation Database.

The data covers the Americas including Hawaii between about 21° South latitude (about 300 km North of Sao Paolo, Brazil) to about 60° North (about 200 km south of Anchorage, Alaska), and the Indian subcontinent and parts of Central Asia. We recommend that you use the new data, but you can still use legacy data if needed.



We also changed some labels, updated a few default values, and revised the Help documentation. See What's New above for details.

