How Much Will Solar Save You?

How Much Solar Do I Need?

Start with your electricity bill. Take the units you use in a month (average a summer and a winter bill) and divide by 120 — the units one kW of solar panels makes in a month in most of India.

• 150–250 units a month → 1.5–2 kW
• 300–400 units a month → 3 kW (3 kW price)
• 500–650 units a month → 5 kW (5 kW price)
• 1,000–1,300 units a month → 10 kW (10 kW price)

Then check your roof: you need about 100 sq. ft. of shade-free space per kW, and your sanctioned load should be at least the system size (your DISCOM can raise it if not).

Solar Savings: A Worked Example

A home paying ₹3,000 a month at ₹7 a unit uses about 429 units. A 3 kW system makes about 360 units a month, saving roughly ₹2,520 a month. It costs about ₹1.93 lakh; the ₹78,000 subsidy brings that to ₹1.15 lakh.

Solar Payback Period

The payback period is how long your bill savings take to cover what you paid: net cost ÷ yearly savings. In the example above that’s about 3.8 years. Higher tariffs, the subsidy, and using solar power in the daytime all shorten it.

Solar ROI

Panels are warrantied to keep producing for 25 years, so everything after the payback period is profit. In the example, 25 years of savings come to about ₹10.31 lakh — a return of about 800% on the money spent, allowing for rising tariffs and slow panel ageing. Few investments a household can make return as much, as safely.

Want to compare prices first? See the solar panel price list or how the PM Surya Ghar subsidy works.