Cost per watt is the all-in installed price divided by total watts. 75/W including panels, inverter, mounting hardware, wiring, installation labor, permits, and interconnection fees. Get quotes from 3+ installers to find your actual cost. Historic Low Pricing: Solar costs have reached unprecedented lows in 2025, with systems ranging from $2. Federal Tax Credit Urgency: With Congress proposing to end the 30% federal tax credit after 2025, homeowners. Solar panels cost $2. For a typical 8 kW residential system, that is $20,000–$28,000 before incentives. 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.