In 2025, a 20 kW solar panel system costs around $47,600 before incentives, based on real installation data from across the country. But your actual price will depend on factors like your roof's complexity, local labor costs, the equipment you choose, and what incentives are. This high-power, low cost solar energy system generates 20,060 watts (20 kW) of grid-tied electricity with (34) 590 watt Axitec XXL bi-facial model PS590M8GF-24/TNH, SMA Sunny Boy Smart Energy inverter, Sunny Portal 24/7 monitoring, disconnect box,. This affordable, high-efficiency 20. This system size is designed to offset the high energy consumption of large homes or provide significant power for a business. 20kW Solar System: Price, Load Capacity, How Big, and More - Solar Panel Installation, Mounting, Settings, and Repair.