Compare loan terms, rebates, and energy bill savings. See payments, cash flow, and payback fast. Plan your solar upgrade with confident financial clarity now.
| Gross Cost | Rebate | Down Payment | Rate % | Term | kWh (Y1) | Tariff | Escal % |
|---|---|---|---|---|---|---|---|
| 1,800,000 | 150,000 | 300,000 | 14 | 7 | 12,000 | 55 | 6 |
| 2,400,000 | 200,000 | 400,000 | 13 | 8 | 16,000 | 60 | 7 |
| 1,250,000 | 100,000 | 250,000 | 15 | 6 | 9,500 | 50 | 5 |
Loan rate, term length, rebates, and down payment change the investment profile. A higher down payment lowers interest and improves monthly cash flow, but it increases equity at risk. Longer terms reduce the monthly bill yet can push payback later. This calculator combines these drivers so you can compare offers consistently, using the same energy assumptions and timeline.
Cash flows are modeled yearly. Energy savings appear every year, while debt service stops when the loan ends. Incentives can be applied in a chosen year, which matters because earlier credits improve both NPV and payback. The table highlights the year when cumulative cash flow crosses zero, helping teams plan capital recovery alongside construction milestones and maintenance schedules clearly.
Energy value depends on tariff, escalation, and how much generation offsets onsite use. Net metering factor represents the value of each kilowatt hour relative to retail billing. If surplus is exported, the export share and export factor reduce revenue compared with self use. With these levers, you can model conservative credit policies or full retail netting.
Operations and maintenance include cleaning, monitoring, minor repairs, and inverter reserves. Annual escalation reflects service inflation. Small O&M changes can meaningfully affect long horizons, especially after the loan ends when savings dominate. Use contractor quotes and historical service costs from similar installations to keep projections defensible during procurement and stakeholder review.
Simple payback is intuitive, but it ignores the time value of money. NPV discounts each year’s net cash flow using your selected discount rate, capturing project risk and alternative capital uses. IRR summarizes the return as a single percentage based on equity cash flows. Use all three metrics together to balance speed, value, and overall return. Document assumptions, run low and high cases, and export reports to align finance, design, and ownership decisions across the project team.
ROI compares total net benefits over the analysis period against your upfront equity outlay. It reflects savings, O&M, debt service, and any incentive credited in the chosen year.
Many projects treat equity as the capital at risk while debt is repaid from operations. Using down payment focuses on shareholder exposure and shows how financing changes returns.
Set an export share and an export rate factor. Exported energy is valued lower than self use when credits are discounted, reducing annual savings and lengthening payback.
Use your hurdle rate or weighted cost of capital. Higher discount rates reduce NPV and emphasize early cash flows, which is helpful when risk or opportunity cost is high.
IRR requires at least one negative cash flow and one positive cash flow. If cash flows never turn positive, or they change sign multiple times, IRR may be undefined.
Not always. Payback ignores cash flows after breakeven and time value. Review payback with NPV and IRR to capture long term value and financing impacts.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.