How big is a solar panel? Post Author:brennenlesser Post published:January 15, 2020 Post Category:FAQ The average size of most panels for rooftop solar installation is about 65″(5.4 ft) by 39″(3.25ft) You Might Also Like What are solar panels made of? January 15, 2020 What can I do to lower my energy consumption? January 14, 2020 Why is solar power the best energy source? January 15, 2020