On average, monocrystalline solar panels (the most energy-efficient option) cost Rs. 43 to Rs. 63 per watt, meaning that outfitting a 3kW solar panel system (also known as a solar system) costs between Rs. 2,25,000 to Rs. 3,00,000 for grid connected solar system and Rs. 2,50,000 to 3,50,000 for standalone solar system.