Solar Panel Calculator: ROI, Savings & Payback Period
Rooftop Solar in India: The Numbers
A 3 kW rooftop solar system costs ₹1.5–2.5 lakh (after subsidy) and generates 12–15 units/day. With net metering, you can cut your electricity bill by 70–90%. The central government offers up to ₹78,000 subsidy under PM Surya Ghar.
System Size by Consumption
| Monthly Bill | Units/Month | Recommended System | Cost (after subsidy) |
|---|---|---|---|
| ₹2,000–3,000 | 200–300 | 2 kW | ₹1.0–1.4L |
| ₹3,000–5,000 | 300–500 | 3 kW | ₹1.5–2.0L |
| ₹5,000–8,000 | 500–800 | 5 kW | ₹2.5–3.5L |
| ₹8,000+ | 800+ | 7–10 kW | ₹4.0–7.0L |
ROI & Payback Period
- Average payback: 4–6 years (depending on tariff rates)
- Panel lifespan: 25 years (with 80% efficiency at year 25)
- Effective ROI: 15–25% annually after payback
- Maintenance: ₹2,000–5,000/year (panel cleaning, inverter check)
Net Metering: How It Works
Excess solar electricity is exported to the grid. Your meter runs backward. At month-end, you pay only the net difference. Some states offer ₹2–3/unit for exported power.
Calculate your solar savings and payback with the solar panel calculator. Compare with your current electricity bill.