📊 Solar Panel ROI Calculator

The ROI Math (Worked for a 3 kW System)

Here is the exact computation the calculator runs, using the MNRE benchmark cost of ₹50,000/kW and ₹8/unit electricity:

1. System cost: 3 kW × ₹50,000 = ₹1,50,000 (MNRE benchmark, 2026)
2. PM Surya Ghar subsidy: ₹30,000 × 2 + ₹18,000 × 1 = ₹78,000
3. Net cost (what you pay): ₹1,50,000 − ₹78,000 = ₹72,000
4. Annual generation: 3 kW × 4.5 PSH × 365 = 4,860 kWh/year
5. Annual savings: 4,860 × ₹8 = ₹38,880/year
6. Payback (flat rate): ₹72,000 ÷ ₹38,880 = 1.9 years
7. 25-year savings (flat): ₹38,880 × 25 = ₹9,72,000
8. 25-year ROI multiple: ₹9,72,000 ÷ ₹72,000 = 13.5x

Cost benchmark per MNRE rooftop solar guidelines, 2026. Subsidy per pmsuryaghar.gov.in (PM Surya Ghar Muft Bijli Yojana, 2026). Generation uses India average of 4.5 peak sun hours; actual output is 10-15% lower after system losses (inverter, wiring, temperature, soiling).

ROI Comparison Table: 1 kW to 10 kW

The return on investment changes with system size because the subsidy caps at 3 kW. Smaller systems get a higher subsidy percentage; larger systems spread the fixed ₹78,000 across more panels.

All figures at ₹8/unit and 4.5 PSH, flat rate (no escalation). The 3 kW row is highlighted because it's the last size where the full ₹78,000 subsidy applies. Note how the ROI multiple drops from 16x at 1-2 kW to 8x at 10 kW — the subsidy dilution is the driver.

Why 25-Year ROI Is the Number That Matters

Solar panels carry a 25-year performance warranty — they lose about 0.5% efficiency per year but remain productive for decades. The real financial picture isn't the 2-year payback; it's the 23 years of nearly free electricity after payback. On a 3 kW system:

• Years 1-2: You recover your ₹72,000 investment through electricity savings.
• Years 3-25: You generate roughly ₹38,000/year in savings with no fuel cost — that's ₹8.7 lakh of free electricity over the remaining 23 years.
• Inverter replacement (~year 10-12): Budget ₹8,000-15,000 for one inverter swap. Even after this cost, your net 25-year ROI is above ₹9 lakh.

No other household investment returns 13x over 25 years with this level of certainty — the sun generates the same units regardless of stock market conditions.

Common Advice vs Reality: "3.5 to 5 Year Payback"

Most solar blogs quote a 3.5-5 year payback. That figure is calculated on the gross pre-subsidy cost (₹1.5 lakh for a 3 kW system), not on what you actually pay after the PM Surya Ghar subsidy. Gross payback = ₹1,50,000 ÷ ₹38,880 = 3.9 years. Net payback = ₹72,000 ÷ ₹38,880 = 1.9 years. If a source quotes 3.5-5 years without specifying "pre-subsidy," it's using the gross figure — which understates the real return by ignoring the subsidy you receive.

The Common Mistake: Comparing Solar ROI to FD Returns

People compare solar's 13x over 25 years to a fixed deposit's 7% annual return and conclude solar is worse. This misses two things: (1) solar savings are tax-free (you're not paying tax on avoided electricity costs), and (2) electricity rates escalate 3-5% per year, so your "returns" grow annually while an FD's rate is fixed. With 5% escalation, the 25-year savings jump from ₹9.7 lakh to ₹18.5 lakh — equivalent to a 15% annualised tax-free return on your ₹72,000 investment.

Edge Case: What If Rates Don't Rise?

If electricity tariffs stay flat for 25 years (unlikely, but the conservative case), a 3 kW system still returns ₹9.7 lakh on a ₹72,000 investment — a 13.5x return. Even in the worst realistic scenario (flat rates, 0.5% annual panel degradation, one inverter replacement), the net ROI stays above ₹8 lakh. The downside is limited because your input cost is fixed (₹72,000) while your savings are bounded below by the current electricity rate.

Decision Framework: Should You Invest?

• ROI above 10x (25-year): Yes. This is the typical case for 1-3 kW systems with PM Surya Ghar subsidy and bills above ₹2,000/month. The payback is under 2 years.
• ROI 6-10x: Still yes, but payback stretches to 3-4 years. Usually means a 4-5 kW system where the unsubsidized kW pulls the average down.
• ROI below 6x: Check your inputs. Usually means a very low electricity rate (₹4-5/unit states like Goa, Sikkim) or a very large system. Solar still pays back, but less impressively.
• Planning to move within 5 years: Factor in the home value premium from solar, not just electricity savings. A paid-off solar system typically adds ₹50,000-1,50,000 to home value.

The 2-Minute Self-Check

1. Enter your system size, state's peak sun hours, and electricity rate in the calculator above.
2. Check the net cost — it should be roughly (system kW × ₹50,000) minus ₹78,000 (for systems 3 kW+). If an installer quoted you far more, ask why.
3. Check the 25-year ROI. If it's above 10x, the investment is clear.
4. Subtract ₹15,000 for a future inverter replacement. If the ROI is still above 8x, proceed.
5. Compare the annual savings to your current electricity bill. If savings exceed your bill, you're generating surplus — check net metering credits at the Net Metering Calculator.

Your Next Steps

1. Run the ROI calculator with your actual system size and state's electricity rate.
2. Check your PM Surya Ghar subsidy to confirm your net cost.
3. See the exact year-by-year payback at the Payback Period Calculator.
4. If you haven't sized your system yet, use the Panel Size Calculator.
5. Register at pmsuryaghar.gov.in to claim your subsidy — it's released only through the national portal.

Editor Note

Reviewed June 2026. ROI calculations use MNRE benchmark cost (₹50,000/kW) and PM Surya Ghar subsidy. The 25-year savings projection assumes 0.5% annual panel degradation and does not include inverter replacement costs unless noted. If you spot an outdated figure, please contact us.