4.3 peak sun hours/day average. Residential electricity rate: 13.9¢/kWh.
Installed cost at 2.75$/W, accounting for 20% system-loss derate (inverter, wiring, soiling, temperature).
| System | Annual kWh | Annual Savings | Installed Cost | Payback |
|---|---|---|---|---|
| 4 kW | 5,026 kWh | $698.59 | $11,000 | 15.7 years |
| 6 kW | 7,539 kWh | $1,047.89 | $16,500 | 15.7 years |
| 8 kW | 10,052 kWh | $1,397.18 | $22,000 | 15.7 years |
No incentives assumed: The federal residential solar investment tax credit ended after 2025. Some states and utilities still offer rebates or performance-based incentives; check with your utility.
Full self-consumption or net metering: Savings assume you use all generation on-site or export at retail rates via net metering. Some utilities buy surplus power at wholesale rates, which would reduce savings.
Your site specifics matter: Roof shade, orientation, system degradation, and your actual utility tariff (demand charges, time-of-use rates, fixed fees) can significantly change payback.
Model your own system →