Solar Panel Savings Calculator India - ROI & Payback
Calculate solar panel savings, ROI, payback period, and CO2 reduction for your home or business in India. Estimate system size, cost, and monthly bill savings.
About this calculator
Enter your monthly units, tariff, roof area and sunshine level to estimate the system size, cost, subsidy, yearly savings, payback period and CO₂ avoided.
Choose a panel size and subsidy percentage to see how they change the result.
How to use it
- Enter monthly units and tariff.
- Enter roof area and pick sunshine and panel.
- Set the subsidy % and press Calculate Solar Savings.
Sizing and payback
A 1 kW rooftop system produces about 4 units a day, or roughly 1,400 to 1,500 units a year, in most of India. A home using 300 units a month (3,600 a year) needs about 2.5 to 3 kW. Roof needs about 10 square metres (around 100 sq ft) per kW. Payback = net cost ÷ yearly savings. Under the PM Surya Ghar scheme, the central subsidy has been ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, capped at ₹78,000, so check the portal for current terms and eligibility. Panels degrade about 0.5% a year and are typically warranted for 25 years.
Worked example
3 kW system, ₹7 per unit, 4 units/kW/day
| Annual generation | 3 × 4 × 365 = 4,380 units |
| Annual saving | 4,380 × 7 = ₹30,660 |
| System cost (assume ₹65,000 per kW) | ₹1,95,000 |
| Subsidy | ₹78,000 |
| Net cost | ₹1,17,000 |
| Payback | about 3.8 years |
Tips and common mistakes
- Get 3 quotes and compare per-kW prices.
- Use a net-metering connection where available.
- Shade ruins output; check the roof for shadows.
- Clean panels every few weeks in dusty areas.
- Confirm the subsidy and net-metering rules with your DISCOM.
Frequently asked questions
How much does a rooftop solar system cost?
Roughly ₹50,000 to ₹70,000 per kW before subsidy, varying by brand.
How many units does 1 kW produce?
About 4 units per day.
What is the payback period?
Often 3 to 6 years with subsidy.
How long do panels last?
25 years or more.
Do I need a battery?
Not for grid-tied net metering.
What is the subsidy?
See the PM Surya Ghar portal for current figures.