See your solar payback year at a glance. Model utility rates, incentives, and system performance. Download a timeline report and decide with confidence today.
| Scenario | System (kW) | Annual production (kWh) | Monthly use (kWh) | Rate per kWh | Upfront cost | Escalation | Payback (yrs) | 25-year net savings |
|---|---|---|---|---|---|---|---|---|
| Typical household | 6.0 | 9,000 | 900 | $0.16 | $15,000 | 3% | 8–12 | $20k–$60k |
| Higher utility rates | 6.0 | 9,000 | 900 | $0.28 | $15,000 | 3% | 5–8 | $45k–$100k |
| Lower export credit | 6.0 | 9,000 | 900 | $0.16 | $15,000 | 3% | 10–16 | $10k–$35k |
A timeline starts with production and the bill you avoid. For example, a 6.0 kW system at 1,500 kWh/kW/yr produces about 9,000 kWh in year one. If your value is $0.16/kWh, that is roughly $1,440 of annual value before O&M and financing. Self-consumption matters: using 70% on-site and exporting 30% at full credit keeps most value close to the retail rate.
Escalation compounds every year. At 3% escalation, the energy rate is about 1.34× higher after 10 years and about 2.03× higher after 24 years. Because savings track the utility rate, higher escalation pushes cumulative cashflow upward faster, even while production declines with degradation. If you expect flat rates, the payback year can move later and NPV can compress.
Cash purchases usually show a large year‑0 outlay followed by positive cashflows. Loans replace most upfront cost with annual payments, so early net cashflow can be smaller even when the system saves energy. Leases/PPA-style plans often start near zero upfront, but the lease payment (and any escalator) reduces annual net cashflow. Compare models by total net savings and by payback year, not by first-year savings alone.
Most systems have low routine costs, but the timeline improves when you budget realistically. If annual O&M is $200 and insurance is $0, that is $5,000 over 25 years before discounting. Setting an inverter replacement of $1,200 in year 12 creates a dip in cumulative cashflow. Storage can amplify savings when self-consumption rises, but replacement assumptions should be included for conservative planning.
NPV translates future cashflows into today’s money using your discount rate. If NPV is positive at 6%, the project outperforms a 6% hurdle on a present-value basis. IRR is the break‑even discount rate; if IRR is 9% and your discount rate is 6%, you have a three‑point cushion. Use NPV for ranking options and IRR for a “attractive or not” check.
Payback is the first year where cumulative cashflow reaches zero or above after costs, payments, replacements, and credits. If it shows “Not reached”, the modeled cumulative cashflow stays negative across your selected horizon.
Use self-consumption to reflect how much solar you use instantly on-site. Set export credit to represent what exported energy earns versus your retail rate. Full net metering is 100%; partial credits might be 30–80%, depending on policy.
The model subtracts the estimated solar value from the baseline bill. If production is high and export credit is generous, savings can exceed the baseline energy charge. Fixed monthly charges still remain, so realistic settings keep results grounded.
Instant rebates and other upfront incentives reduce the initial cost. A tax credit is modeled as a one-time cash inflow in the year you specify. Lease/PPA results set tax credit to zero because the system owner typically claims it.
Yes. Annual production declines by the degradation rate you enter, compounding each year. Optional inverter and battery replacements add one-time costs in their specified years, which can create a dip in cumulative cashflow and affect payback.
Lower export credit, reduce specific yield, and increase O&M or replacement costs to stress-test assumptions. You can also raise the discount rate to reflect higher opportunity cost. Compare scenarios side-by-side by downloading the CSV.
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.