Enter an installed quote, a verified incentive, annual energy valued at the rate it offsets, and an assumed annual degradation. The federal residential clean-energy credit is unavailable for property placed in service after December 31, 2025. The default incentive is zero; a state or utility program needs its own eligibility check.
Solar Payback: worked example
| System cost before incentives | $18,000 |
|---|---|
| Verified incentive | 0.000% |
| Annual production (kWh) | 9,000 |
| Electricity price per kWh | $0.17 |
| Yearly output decline | 0.500% |
| Simple payback | 11.8 years |
| Cost after incentive | $18,000 |
| Net savings over 25 years | $18,041 |
Solar Payback: changing Electricity price per kWh
| Electricity price per kWh | Simple payback | Cost after incentive | Net savings over 25 years |
|---|---|---|---|
| $0.14 | 14.3 years | $18,000 | $11,680 |
| $0.15 | 13.3 years | $18,000 | $13,801 |
| $0.17 (example) | 11.8 years | $18,000 | $18,041 |
| $0.19 | 10.5 years | $18,000 | $22,281 |
| $0.20 | 10.0 years | $18,000 | $24,401 |
Solar Payback: compare input ranges
| Input | Tested from | To | Simple payback: low input | Simple payback: high input | Swing |
|---|---|---|---|---|---|
| Electricity price per kWh | $0.15 | $0.19 | 13.3 years | 10.5 years | 2.8 years (24%) |
| Annual production (kWh) | 8,100 | 9,900 | 13.1 years | 10.7 years | 2.4 years (20%) |
| System cost before incentives | $16,200 | $19,800 | 10.6 years | 12.9 years | 2.4 years (20%) |
| Verified incentive | -0.250% | 0.250% | 11.8 years | 11.7 years | 0.1 years (0.5%) |
| Yearly output decline | 0.250% | 0.750% | 11.8 years | 11.8 years | 0.0 years |
Solar Payback: individual input comparisons
| Input | Value | Simple payback | Cost after incentive | Net savings over 25 years |
|---|---|---|---|---|
| System cost before incentives | $14,400 | 9.4 years | $14,400 | $21,641 |
| $16,200 | 10.6 years | $16,200 | $19,841 | |
| $18,000 | 11.8 years | $18,000 | $18,041 | |
| $19,800 | 12.9 years | $19,800 | $16,241 | |
| $21,600 | 14.1 years | $21,600 | $14,441 | |
| Verified incentive | -0.500% | 11.8 years | $18,090 | $17,951 |
| -0.250% | 11.8 years | $18,045 | $17,996 | |
| 0.000% | 11.8 years | $18,000 | $18,041 | |
| 0.250% | 11.7 years | $17,955 | $18,086 | |
| 0.500% | 11.7 years | $17,910 | $18,131 | |
| Annual production (kWh) | 7,200 | 14.7 years | $18,000 | $10,832 |
| 8,100 | 13.1 years | $18,000 | $14,437 | |
| 9,000 | 11.8 years | $18,000 | $18,041 | |
| 9,900 | 10.7 years | $18,000 | $21,645 | |
| 10,800 | 9.8 years | $18,000 | $25,249 | |
| Electricity price per kWh | $0.14 | 14.3 years | $18,000 | $11,680 |
| $0.15 | 13.3 years | $18,000 | $13,801 | |
| $0.17 | 11.8 years | $18,000 | $18,041 | |
| $0.19 | 10.5 years | $18,000 | $22,281 | |
| $0.20 | 10.0 years | $18,000 | $24,401 | |
| Yearly output decline | 0.000% | 11.8 years | $18,000 | $20,250 |
| 0.250% | 11.8 years | $18,000 | $19,124 | |
| 0.500% | 11.8 years | $18,000 | $18,041 | |
| 0.750% | 11.8 years | $18,000 | $16,998 | |
| 1.0% | 11.8 years | $18,000 | $15,993 |
Solar Payback: combined input changes
| Electricity price per kWh / System cost before incentives | $14,400 | $18,000 | $21,600 |
|---|---|---|---|
| $0.14 | 11.4 years | 14.3 years | 17.1 years |
| $0.15 | 10.7 years | 13.3 years | 16.0 years |
| $0.17 | 9.4 years | 11.8 years | 14.1 years |
| $0.19 | 8.4 years | 10.5 years | 12.6 years |
| $0.20 | 8.0 years | 10.0 years | 12.0 years |
Solar Payback: which assumptions move the result?
Solar Payback: values and definitions
| Quantity and definition | Value used |
|---|---|
| System cost before incentives | $18,000 |
| Verified incentive — Enter only a confirmed applicable incentive. The federal residential clean-energy credit ended for property placed in service after 2025. | 0.000% |
| Annual production (kWh) | 9,000 |
| Electricity price per kWh | $0.17 |
| Yearly output decline — Panels lose a little output each year. | 0.500% |
| Simple payback | 11.8 years |
| Cost after incentive | $18,000 |
| Net savings over 25 years | $18,041 |
Solar Payback: half and double Electricity price per kWh
| Electricity price per kWh | Simple payback |
|---|---|
| $0.09 | 23.5 years |
| $0.17 | 11.8 years |
| $0.34 | 5.9 years |
Payback depends on net metering, which decides what you are paid for excess power, and on rate changes. The estimate ignores inverter replacement, insurance and maintenance, and the time value of money. Incentives change and may phase out.
A roof that needs replacing first changes the economics.
Solar Payback: formula
U.S. Department of Energy: Homeowner's Guide to Going Solar · IRS: Residential clean-energy credit
Common error: Holding the electricity price flat forever or assuming it climbs forever. Both are guesses, so run the number at a lower and a higher rate before you sign.
Energy & Utilities calculators: LED Bulb Savings Calculator, Generator Size Calculator, Electricity Cost Calculator, EV Charging Cost Calculator, MPG Calculator, Battery Runtime Calculator.
Payback is the cost after incentives divided by the yearly savings. An $18,000 system with a 30 percent credit costs $12,600. At 9,000 kilowatt-hours and 17 cents a unit, that saves $1,530 a year and pays back in about eight years.
The 25-year figure trims each year's output a little, because panels fade, so it lands lower than eight times 25 would suggest.
Confirm the incentive still applies to your system and your tax situation, and use your real rate, since it changes the payback more than any other input.
Estimate the production on the solar panel output calculator, current costs on the electricity cost calculator and financing on the loan calculator. The battery runtime and generator size pages cover backup, and the net present value and payback period calculators explain the finance.
Does simple payback account for degradation?
The first result divides net cost by first-year savings. The separate 25-year calculation applies the entered degradation, without discounting future cash flow.
How long does it take for solar panels to pay for themselves?
Simple payback compares cost with annual savings. Use net eligible installation cost. Six or twelve years is a scenario.
It is not a universal U.S. range. Tariffs, export credits, financing, maintenance and incentive eligibility can change the actual timeline; the assumed annual savings need support before a division result can describe that project.
Do solar panels lose output over time?
Use the specific module’s performance warranty and the project’s degradation assumption. A 0.5% annual loss or 80%–90% retained output after 25 years is a scenario until supported by that product’s documents. A warranty threshold also differs from a forecast of annual energy delivered by the whole system.
Does net metering affect payback?
Yes. Full retail credit for excess power shortens the payback, while lower buyback rates lengthen it.