The average cost of installing a commercial solar panel system. System size (kW) Average price Expected price range 25 kW $50,211 $43,750 - $56,350 50 kW $100,423 $87,500 - $112,700 100 kW $200,846 $175,000 - $225,400 250 kW $502,113 $437,500 - $563,500