The average cost of solar panels ranges from $2. 50 per watt installed, with most homeowners paying between $15,000 and $35,000 for a complete system before incentives. 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. solar photovoltaic (PV) systems to develop cost benchmarks. solar calculator — enter your ZIP code and electricity bill, and it returns your recommended system size in kW, the number of panels, the roof area you need, the gross install cost, the annual savings, the payback period, the 25-year lifetime profit, and the CO₂ offset. – that's 50% cheaper than a decade ago! But why does your neighbor's quote look different? Three key factors: Data sources: SEIA 2023 Report, German Solar Association It's not just about panel.