Solar Loan Calculator
Work out the monthly payment on a solar loan and compare it with what the panels save on your bill.
Your result
Enter your numbers and press the button. Your result appears here.
Compare the loan payment with the bill savings. If the savings are larger, solar pays for itself from the first month.
How it works
Payment = P × r ÷ (1 − (1 + r)^−n), where P is the amount borrowed, r the monthly rate (APR ÷ 12) and n the number of months.
Example: $20,800 at 7% for 20 years is $161 a month, $17,903 in interest.
At a glance
Same settings as the calculator, changing only the apr.
| APR | Monthly | Interest | Total paid |
|---|---|---|---|
| 0% | $87 | $0 | $20,800 |
| 3.99% | $126 | $9,424 | $30,224 |
| 5.99% | $149 | $14,935 | $35,735 |
| 7.99% | $174 | $20,924 | $41,724 |
| 9.99% | $201 | $27,341 | $48,141 |
| 11.99% | $229 | $34,131 | $54,931 |
Common questions
Is a solar loan worth it?
When the monthly bill savings are larger than the loan payment, the system pays for itself from day one. Longer terms lower the payment but add interest.
Do solar loans have hidden fees?
Some solar loans add a dealer fee to the amount financed in exchange for a lower advertised rate. Ask for the cash price and compare.
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.
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/