Solar Installation Estimator – Reference Data
This calculator estimates total residential solar cost using the common industry pricing method of $/W installed. To calculate system size, multiply the number of panels by the wattage rating of each panel (most modern panels are typically 350–450 watts, often around 400W).
Typical Panel Count: Many U.S. homes require roughly 16–23 panels depending on electricity usage, roof space, and panel wattage.
Installed Cost Per Watt: Residential rooftop solar is commonly priced around $2.50–$3.50 per watt installed before incentives. U.S. Department of Energy benchmarks report a modeled residential rooftop market price around $3.15/W.
Example Calculation:
18 panels × 400W = 7,200W (7.2 kW system)
7,200W × $2.50–$3.50/W ≈ $18,000–$25,200 installed before incentives.
Discount Percent: Homeowners may qualify for the federal Residential Clean Energy Credit, which provides a 30% tax credit for eligible solar installation costs through December 31, 2025.
Sources:
EnergySage – Average number of panels needed
U.S. DOE – Residential solar cost benchmarks ($/W installed)
Solar.com – Typical installed solar pricing ranges
IRS – Residential Clean Energy Credit (30% federal tax credit)