As of 2026, the average cost of a 20kW solar system in the United States ranges from $41,000 to $64,000 before incentives or rebates. This price includes equipment, installation, and associated costs. NLR analyzes the total costs associated with installing photovoltaic (PV) systems for residential rooftop, commercial rooftop, and utility-scale ground-mount systems. This work has grown to include cost models for solar-plus-storage systems. If you're deciding between roof-mount, ground-mount, tracking, or even floating systems, understanding the cost breakdown for each is crucial. Combined with the tax. Each year, the U. Department of Energy (DOE) Solar Energy Technologies Office (SETO) and its national laboratory partners analyze cost data for U.