Your home solar, worked out
A worked example
Take a home that pays ₹2,500 for 300 units a month. That is ₹8.33 a unit. At 120 units a month for each kW, it needs a 2.5 kW system on about 250 sq ft of shade-free roof. A 2.5 kW system typically costs ₹2.05 to ₹2.15 lakh installed. The PM Surya Ghar subsidy of ₹69,000 brings that down to ₹1.36 to ₹1.46 lakh. The bill falls by about ₹30,000 a year, so the money comes back in 4.5 to 4.9 years.
Pick your state in the calculator and the numbers change. The same 300 units need 2.5 kW in Rajasthan but 3.5 kW in Sikkim, where the sun is weaker and the hill-state subsidy is higher.
How the calculator works
- Your bill divided by your units gives what you pay per unit today. This is the rate every solar unit saves.
- Your monthly units divided by what 1 kW makes in your state gives the size, rounded up to the next half kW. Across India, 1 kW makes about 120 units a month. If you enter a roof area, the size is capped at 100 sq ft per kW.
- The installed price comes from published 2026 ranges. Enter your installer’s quote and it replaces the range with one number.
- The subsidy follows the PM Surya Ghar rules for your state. Payback is the cost after subsidy divided by a year of bill savings.
What a home system costs in 2026
| System | Installed price | Central subsidy | After subsidy | Units a month |
|---|---|---|---|---|
| 1 kW | ₹1.2 lakh to ₹1.3 lakh | ₹30,000 | ₹0.9 lakh to ₹1 lakh | 120 |
| 2 kW | ₹1.8 lakh to ₹1.9 lakh | ₹60,000 | ₹1.2 lakh to ₹1.3 lakh | 240 |
| 3 kW | ₹2.3 lakh to ₹2.4 lakh | ₹78,000 | ₹1.52 lakh to ₹1.62 lakh | 360 |
Above 3 kW the subsidy stays at ₹78,000, so each extra kW costs you the full price. It still pays off if you use the units, but check your roof and sanctioned load first. The subsidy calculator shows the exact amount for your state and size.
Is solar worth it at your electricity rate?
The higher your per-unit rate, the faster solar pays back. For a 3 kW system costing about ₹1.57 lakh after subsidy, with all 360 units used at home:
| You pay per unit | Saving a year | Payback (years) |
|---|---|---|
| ₹6 | ₹25,920 | 6.1 |
| ₹7 | ₹30,240 | 5.2 |
| ₹8 | ₹34,560 | 4.5 |
| ₹9 | ₹38,880 | 4.0 |
| ₹10 | ₹43,200 | 3.6 |
Panels come with 25 to 30 year output warranties, so even a six-year payback leaves close to two decades of cheaper power. If your rate is below ₹5, the case is weaker and a smaller system may make more sense.
Before you sign
- Apply on pmsuryaghar.gov.in and choose a registered vendor before any work starts.
- Ask for DCR panels on the ALMM list in writing. Without them the subsidy claim is rejected.
- Get the price split into panels, inverter, structure and net meter so you can compare quotes.
- Check that your sanctioned load is at least the system size. Your DISCOM can raise it if not.
Frequently asked questions
What size solar system do I need for my home?
Divide the units on a typical monthly bill by 120. A home using 300 units a month needs about 2.5 kW, and one using 450 units needs about 4 kW. Sunnier states need a little less.
How much does a 3 kW solar system cost after subsidy?
A 3 kW rooftop system costs about ₹2.30 to ₹2.40 lakh installed in 2026. After the ₹78,000 PM Surya Ghar subsidy you pay about ₹1.52 to ₹1.62 lakh.
How long does home solar take to pay back?
Usually four to six years. At ₹8 a unit a 3 kW system pays back in about four and a half years; at ₹6 a unit it takes about six.
Does this calculator include net metering?
It counts only the units you use yourself. Extra units you export earn credit under your state’s net metering rules, which would shorten the payback further.
Can I pay in EMIs?
Yes. Loans under PM Surya Ghar start at 5.75% a year for up to ₹2 lakh. The solar EMI calculator works out the monthly payment.
See the formulas and sources on how we calculate. For the full subsidy process, read PM Surya Ghar subsidy 2026: how much you get and how to apply.