Solar Panels ROI Calculator
Estimate payback time, lifetime savings, and NPV for a residential solar system with incentives, degradation, and utility rate inflation.
System & Incentives
Rates & Operations
Investing & Buying Assumptions
Net upfront cost
$14,000
Year-1 production
10,500 kWh
Year-1 bill savings
$2,163
Results
Payback year
Year 7
25-yr net savings
$52,285
NPV
$17,619
IRR
15.95%
Timeline
Cumulative net cashflow
Email my calculations
Receive a printable breakdown (PDF) to revisit your calculations later.
Upfront net cost of $14,000 pays back in year 7. Estimated 25-year net savings: $52,285.
Year-by-year cashflow
| Year | Production (kWh) | Retail rate | Bill savings | Maintenance | Capex | Net | Cumulative |
|---|---|---|---|---|---|---|---|
| 0 | 0 | $0.260/kWh | $0 | $0 | $14,000 | -$14,000 | -$14,000 |
| 1 | 10,500 | $0.260/kWh | $2,163 | $120 | $0 | $2,043 | -$11,957 |
| 2 | 10,448 | $0.268/kWh | $2,209 | $120 | $0 | $2,089 | -$9,868 |
| 3 | 10,395 | $0.276/kWh | $2,257 | $120 | $0 | $2,137 | -$7,731 |
| 4 | 10,343 | $0.284/kWh | $2,305 | $120 | $0 | $2,185 | -$5,546 |
| 5 | 10,292 | $0.293/kWh | $2,355 | $120 | $0 | $2,235 | -$3,311 |
| 6 | 10,240 | $0.301/kWh | $2,406 | $120 | $0 | $2,286 | -$1,024 |
| 7 | 10,189 | $0.310/kWh | $2,459 | $120 | $0 | $2,339 | $1,314 |
| 8 | 10,138 | $0.320/kWh | $2,513 | $120 | $0 | $2,393 | $3,707 |
| 9 | 10,087 | $0.329/kWh | $2,568 | $120 | $0 | $2,448 | $6,155 |
| 10 | 10,037 | $0.339/kWh | $2,624 | $120 | $0 | $2,504 | $8,659 |
| 11 | 9,987 | $0.349/kWh | $2,682 | $120 | $0 | $2,562 | $11,221 |
| 12 | 9,937 | $0.360/kWh | $2,742 | $120 | $1,800 | $822 | $12,043 |
| 13 | 9,887 | $0.371/kWh | $2,803 | $120 | $0 | $2,683 | $14,726 |
| 14 | 9,838 | $0.382/kWh | $2,865 | $120 | $0 | $2,745 | $17,471 |
| 15 | 9,788 | $0.393/kWh | $2,930 | $120 | $0 | $2,810 | $20,281 |
| 16 | 9,739 | $0.405/kWh | $2,995 | $120 | $0 | $2,875 | $23,156 |
| 17 | 9,691 | $0.417/kWh | $3,063 | $120 | $0 | $2,943 | $26,099 |
| 18 | 9,642 | $0.430/kWh | $3,132 | $120 | $0 | $3,012 | $29,111 |
| 19 | 9,594 | $0.443/kWh | $3,203 | $120 | $0 | $3,083 | $32,194 |
| 20 | 9,546 | $0.456/kWh | $3,276 | $120 | $0 | $3,156 | $35,350 |
| 21 | 9,498 | $0.470/kWh | $3,350 | $120 | $0 | $3,230 | $38,580 |
| 22 | 9,451 | $0.484/kWh | $3,427 | $120 | $0 | $3,307 | $41,887 |
| 23 | 9,404 | $0.498/kWh | $3,505 | $120 | $0 | $3,385 | $45,272 |
| 24 | 9,357 | $0.513/kWh | $3,585 | $120 | $0 | $3,465 | $48,737 |
| 25 | 9,310 | $0.529/kWh | $3,668 | $120 | $0 | $3,548 | $52,285 |
source: calestimator.com/solar-roi-calculator
How to use the Solar ROI Calculator
Estimate installation cost, incentives, and utility savings to see how quickly rooftop solar pays for itself.
- Enter system size, equipment type, and installed cost per watt.
- Add federal, state, and utility incentives or tax credits.
- Input your current electricity usage and utility rates.
- Review payback period, lifetime savings, and carbon offset numbers.
Solar ROI Calculator key terms
Knowing how each field influences the results keeps the math grounded in reality.
Net metering
Policy allowing you to sell excess generation back to the grid. It significantly affects ROI.
Degradation rate
How quickly panels lose efficiency over time. Including it keeps savings realistic.
Balance of system
Inverters, racking, wiring, and permitting that add to the turnkey cost beyond panels alone.
Solar ROI Calculator planning ideas
Try running a few “what if” scenarios to translate the numbers into real-world decisions.
Cash purchase vs. loan
Compare paying upfront with financing to see how interest charges affect payback.
Battery storage add-on
Include storage to evaluate resiliency benefits alongside ROI.
Time-of-use rates
If your utility charges more during peak hours, solar plus storage could amplify savings. Model each rate plan.
Frequently asked questions
Do solar panels increase home value?
Studies show owned systems often boost resale value. Use the ROI output as a talking point with appraisers and buyers.
What maintenance is required?
Panels are mostly passive but may need periodic cleaning and inverter replacement. Budgeting for these items keeps ROI projections honest.