About the Solar Rooftop ROI Calculator
Estimate solar project payback and returns from your own system cost, generation, savings and maintenance assumptions.
How to Use This Calculator
Enter your values in the input fields above and click the Calculate button. Results update immediately. You can modify any input and recalculate as many times as needed. All inputs are processed locally in your browser. Optional Save Setup stores the setup only in your browser; Share Setup creates a URL containing encoded setup values. See the Privacy Policy for details.
Formula and Calculation Method
The Solar Rooftop Roi uses the documented calculation method described on this page. Where rules, rates or thresholds can change, review the cited source and effective date shown here before relying on the result for an important decision.
Understanding Your Results
Solar payback and return estimates depend on system cost, generation, tariff, maintenance and financing assumptions. Actual project economics vary by location, installer and utility conditions.
Why Use CalcuTools India
CalcuTools India is an independent, free calculator platform covering personal finance, income tax, salary, loans, investments, retirement planning, and health, with formulas and applicable rules checked against the stated methodology or primary/reference sources where applicable. We are not affiliated with any bank, insurance company, NBFC, or financial products distributor. Our calculators are free to use. Some pages may contain clearly labelled partner or affiliate offers; these do not affect the calculation result.
CalcuTools India · India-focused calculators · Updated September 2026 · About Us · How We Verify · Editorial Policy · Disclaimer
Rooftop Solar ROI Calculator — Is Solar Worth It in India?
With the PM Surya Ghar Muft Bijli Yojana subsidy scheme making rooftop solar more affordable than ever, many Indian households are evaluating whether a solar installation pays for itself. This calculator estimates your payback period and long-term savings based on your actual electricity usage.
How Solar Savings Work
A rooftop solar system generates electricity during daylight hours, directly offsetting what you'd otherwise buy from the grid. Any excess generation can often be exported to the grid under net-metering schemes (varies by state), earning credits against your bill.
Typical Generation in India
A well-positioned rooftop system in most parts of India generates approximately 4 units (kWh) per kW of installed capacity per day, accounting for daylight hours, weather, and panel efficiency. A 3kW system, for example, would generate roughly 12 units/day or 360 units/month.
The PM Surya Ghar Subsidy
The central government subsidy scheme significantly reduces upfront solar costs for residential installations up to 3kW, with additional state-level subsidies in many regions. This calculator should use your post-subsidy system cost for the most accurate payback estimate.
Beyond Pure Financial ROI
Solar also provides protection against rising electricity tariffs (which have historically increased 3-5% annually), reduces dependency on grid power during outages (when paired with battery storage), and contributes to lower carbon footprint — benefits not captured in pure payback period calculations.
Frequently Asked Questions
How long do solar panels actually last? +
Most reputable solar panels carry 25-year performance warranties, guaranteeing at least 80% of original output even after 25 years. Many panels continue producing usable electricity well beyond this warranty period, just at gradually reduced efficiency.
What is net metering and does it matter for this calculation? +
Net metering allows you to export excess solar generation to the grid and receive credit, effectively using the grid as a 'battery'. Availability and credit rates vary significantly by state utility — check your local DISCOM's net metering policy, as it affects your actual realized savings.
Does cloudy weather or monsoon season significantly reduce solar output? +
Yes, generation drops 30-50% during heavy monsoon/cloud cover compared to clear sunny days. The 4 units/kW/day average used in this calculator already accounts for annual weather variation across most of India.
Is rooftop solar worth it if I don't own my home? +
Generally no, unless you have a long-term lease and landlord approval, since the payback period (typically 4-7 years) requires you to remain in the property to realize the savings. Solar makes the most sense for owned properties or long-term rentals with landlord buy-in.
🔄 Last Updated: September 2026 · Rule year is shown where relevant; verify source-linked rules before filing or payment
How It Is Calculated
ROI = Annual Savings / System Cost x 100. Annual savings = Units generated x electricity tariff. 1 kW generates ~4 units/day. PM Surya Ghar subsidy: Rs 78,000 for 3kW.
Worked Example
3 kW rooftop in Delhi. Cost Rs 1,80,000 minus subsidy Rs 78,000 = Rs 1,02,000 net. Generation: 3,600 units/year. At Rs 8/unit: Rs 28,800/year savings. ROI = 28%. Payback = 3.5 years. System lasts 25 years.
Tips
Apply for PM Surya Ghar Yojana subsidy before installation. Net metering available in most states - sell excess units back to grid. Solar panels degrade ~0.5% per year. Inverter typically needs replacement after 10 years.