Solar guide
Solar panel ROI calculator
Estimate the long-term return on investment for a residential solar panel system.
Solar ROI compares the total lifetime financial benefit of a system with the upfront installation cost. It is different from payback, because ROI measures the size of the return, not just the break-even year. For the full formula set, see the methodology page.
Quick ROI estimate
Use annual benefit, system cost and lifetime to estimate long-term ROI.
Estimated ROI
This is a simplified estimate before financing, tax and equipment replacement.
Open full calculatorROI = ((lifetime benefit - installed cost) ÷ installed cost) × 100What does solar ROI tell you?
ROI helps compare the total return from solar against the amount invested. A system with a fast payback can still have a modest ROI if long-term benefit is limited, while a system with a slower payback can still produce a strong ROI over 25 years if electricity savings continue.
Usually comes from lower installed cost, high electricity prices and strong self-consumption.
Can result from expensive installation, low electricity usage, shading or poor tariffs.
A battery can increase self-use, but it must generate enough extra savings to justify its cost.
ROI assumptions to check
- Installed cost after incentives.
- Expected system lifetime.
- Panel degradation rate.
- Current and future electricity prices.
- Self-consumption and export tariff.
- Maintenance, inverter replacement and battery replacement costs.
Solar ROI FAQ
Is ROI the same as payback?
No. Payback estimates when you recover your upfront cost. ROI estimates the total return compared with that cost.
Should ROI include degradation?
Yes. Solar output normally declines gradually, so long-term benefit should be adjusted for degradation.
Can financing change ROI?
Yes. Loan interest, fees and repayment terms can reduce the final return.
What lifetime should I use?
Many solar estimates use 25 years for panel lifetime, but inverters and batteries may need earlier replacement.