Based on our 2025 survey of 1,000 solar customers, the national average price for a single solar panel professionally installed is $1,200. This means most full-size systems of between 20 and 30 panels cost between $24,000 and $36,000. Solar Costs Have Reached Historic Lows: Average residential solar costs have dropped to $3. 30 per watt in 2025, representing a 60% decrease from 2010 levels. Combined with the 30% federal tax credit extended through 2032, most homeowners can achieve payback periods of 6-12 years with 25+. Solar savings are calculated using roof size and shape, shaded roof areas, local weather, local electricity prices, solar costs, and estimated incentives over time. Using a sample address, take a look at the detailed estimate Project Sunroof can give you.