Cost of a 15 kW Solar System
Estimate what a home solar system costs from your electricity use, your bill or a system size, using current installed prices.
Your result
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At the national average of $2.60 per watt, a 15 kW system costs about $39,000 before incentives. Your state's average may be higher or lower.
How it works
Size (kW) = monthly kWh × 12 × share covered ÷ yearly kWh per kW. Cost = size in watts × price per watt + batteries − rebates.
Example: 15.2 kW (38 × 400 W) at $2.60 per watt costs about $39,520 and makes about 20,778 kWh a year.
At a glance
Same settings as the calculator, changing only the price per watt.
| Price per watt | Size | Cost | kWh a year | Payback |
|---|---|---|---|---|
| $2.12 | 15.2 kW | $32,224 | 20,778 | 8.5 yrs |
| $2.40 | 15.2 kW | $36,480 | 20,778 | 9.7 yrs |
| $2.60 | 15.2 kW | $39,520 | 20,778 | 10.5 yrs |
| $2.90 | 15.2 kW | $44,080 | 20,778 | 11.7 yrs |
| $3.20 | 15.2 kW | $48,640 | 20,778 | 12.9 yrs |
| $3.72 | 15.2 kW | $56,544 | 20,778 | 15.0 yrs |
Common questions
How much do solar panels cost in 2026?
EnergySage marketplace quotes average $2.60 per watt nationally, or about $20,800 for an 8 kW system, before incentives. State averages run from $2.12 in Florida to $3.72 in Alabama.
What size solar system do I need?
Divide your yearly use in kWh by the yearly output of 1 kW of panels where you live. The average U.S. home used 865 kWh a month in 2024, which takes about 7.6 kW at the national average output.
Is there still a federal solar tax credit?
Not for homeowners who buy their system. The 30% Residential Clean Energy Credit ended for systems installed after December 31, 2025. Leased systems and PPAs can still carry a business credit (48E) that the installer claims.
Why do solar quotes vary so much?
Equipment is only about a third of the price. Sales, marketing, overhead and profit make up about 40% in EnergySage's breakdown, so installers' prices differ widely.
Sources
- EnergySage, Solar panel cost by state (updated November 6, 2026): https://www.energysage.com/local-data/solar-panel-cost/
- U.S. EIA, Electric Power Monthly, Table 5.6.B (residential price, Jan–Aug 2026): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_b
- NREL PVWatts v8 (20° tilt, south-facing, 14% losses), state results compiled by TheGreenWatt: https://thegreenwatt.com/average-peak-sun-hours-by-state/
- EnergySage, Solar battery backup cost (H1 2026): https://www.energysage.com/energy-storage/solar-battery-backup/