Inputs
Filled in for youTariff rising 0% a year, 25 years, fixed charges, panel wear and inverter
Verdict
Solar pays for itself in 7 years 2 months
After that it keeps cutting your bill: you end ₹4.50 lakh ahead after 25 years.
Solar doesn't pay off in 25 years if it costs more than ₹6.30 lakh after subsidy
This answer uses an example system and bill. Put in your installer's quote and your own bill to get your answer.
- Bills saved₹6.30 lakh
- System cost₹1.80 lakh
- Saving in year 1
- ₹25,200
- Total gain after 25 years
- ₹4.50 lakh
- Yearly return on the cost
- 14.38%
- Share of your use covered, year 1
- 121.67%
Savings minus the net cost and any inverter replacement.
Saved scenarios
What would flip the answer
Each line changes one input and holds the rest.
None of the inputs we test flips the answer within a realistic range.
Not modelled: weigh these yourself
Show the workingEvery step of the sum, with the numbers above.
Show the chart and scenariosHow the gap changes month by month, and how much the answer moves if prices rise faster or slower.
If prices rise faster or slower
Show every monthThe full month-by-month table, with a CSV download.
How this works
Each month, the panels generate system size × generation per kW per day × 365 ÷ 12 units, less a little each year as they age. Your bill is worked out twice: on all the units you use, and on only the units you still buy from the grid, minus credit for any units you send to it. The difference is the saving. Because the bill uses the tariff's slabs, the units you save come off the most expensive slab first. Payback is the month when savings cover the price after subsidy.
Assumptions and sources
| Assumption | Value | Source | As of |
|---|---|---|---|
| UP domestic tariff | —Not verified | UPERC tariff order in force (domestic urban metered category): energy slabs, fixed charge per kW, electricity duty | 2026-10-19 |
| Rooftop solar subsidy | —Not verified | PM Surya Ghar central subsidy for residential rooftop solar, plus any UP state top-up | 2026-10-19 |
| Generation per kW per day | —Not verified | average daily output per kW for UP (e.g. MNRE or PVWatts estimate) | 2026-10-19 |
| Panel output lost each year | —Not verified | panel manufacturer's performance warranty | 2026-10-19 |
| Credit per unit exported | —Not verified | UPERC net-metering regulation (credit for units exported to the grid) | 2026-10-19 |
| Electricity price rise a year (pessimistic / base / optimistic) | 0% / 3% / 5% | CapitalVerdict default assumption from project spec (fuel/tariff rise); user-editable, not a forecast | 2026-10-19 |
Questions
Why are some fields empty?
Subsidy, generation, panel loss and export credit depend on rules and data we have not verified yet, so we do not guess them. Enter the figures from your installer's quote and your bill.
Why do I enter an average price per unit?
Until the UP slab tariff is verified, the tool uses one price for every unit plus your fixed charge. Divide your energy charge and duty by the units on your bill to get it.
What is the yearly return (IRR)?
The interest rate at which the money you put into the system would grow to the same savings. Compare it with what the money would earn elsewhere, after tax.