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Solar Payback
Solar Payback Calculator
Estimate how quickly a rooftop solar system pays for itself and how much it saves you over its lifetime.
Your system
Rs
kW
Rs
Leave 0 to estimate from size.
Rs/kWh
%
Total installed costRs 1,250,000
Estimated payback period
4.6 years
Net savings over 25 years: Rs 5,584,375
Monthly saving
Rs 22,781
Annual saving
Rs 273,375
ROI
21.9 % / year
Monthly generation
675 kWh
Recommended system size
4.0 kW
Smaller than your entered size — you may be over-sizing.
25-year net savings
Rs 5,584,375
How this is calculated
- Monthly generation = system size × peak sun hours × 30 days.
- Daytime self-consumption (units you use as they are generated) saves the full tariff, capped at your current bill. Surplus exported to the grid earns a lower net-metering export credit (~50% of the import tariff).
- A battery lets you store daytime generation for evening use, lifting self-consumption to ~90%.
- Total cost = installation cost, or system size × installed cost per kW when left at 0.
- Payback = total cost ÷ annual saving. ROI = annual saving ÷ total cost (simple annual return).
- Recommended system size is derived from your monthly bill and may differ from the size you entered.
- Simplified model: it does not account for tariff changes, panel degradation, or inverter replacement over time.
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