Money
The only question that matters for most families: after subsidy, will the system pay for itself in a sensible time? Tariff slabs differ by DISCOM — always start from your bill.
Last reviewed
Gross cost is what the installer quotes for panels, inverter, structure, wiring, and related work (before subsidy).
Subsidy (up to ₹78,000) is credited to your bank after commissioning if you qualify under PM Surya Ghar.
Net cost ≈ gross cost − subsidy. That is the investment your monthly bill savings should recover.
Payback ≈ net cost ÷ yearly savings. Under about 5 years is usually attractive for a home with a solid bill; beyond 7–8 years many families wait.
Two things belong in that calculation and are usually left out: ongoing maintenance and one inverter replacement during the plant's life, and the fact that surplus you export is worth less than the units you self-consume. Size-by-size pricing: 1 kW · 2 kW · 3 kW · 5 kW · 10 kW. Cooling-heavy bills: solar panels for an AC.
Ballpark (indicative)
Indicative ranges using domestic tariff logic (~₹63k–₹65k per kW gross; 3 kW ≈ ₹1,90,000 before CFA). Sun hours and slabs vary by city. Your quote will differ — run the free check.
| Size | Gross (indicative) | Subsidy | Net (indicative) |
|---|---|---|---|
| 2 kW | ₹1,27,000 | ₹60,000 | ₹67,000 |
| 3 kW | ₹1,90,000 | ₹78,000 | ₹1,12,000 |
| 5 kW | ₹3,17,000 | ₹78,000 | ₹2,39,000 |
Gross moves with module brand, structure, and labour. Always compare written quotes.
The formula above is simple. Almost every unrealistic projection comes from getting one of its two inputs wrong, and it is usually the savings side rather than the cost side.
Treating every generated unit as worth your retail tariff. This is the biggest single error. A unit you consume while the panels are producing genuinely avoids your full tariff. A surplus unit exported earns whatever the tariff order in force at commissioning allows, which is typically less. A household that is out all day exports a large share of its generation and saves noticeably less than a household with daytime load — same roof, same system, different return. See net metering in India.
Using your highest month as the baseline. Annual savings estimated from a May bill will overstate the year. Use twelve months.
Ignoring your tariff slab structure. Solar removes your most expensive units first, so the saving depends on the marginal rate you are actually reaching, not your average rate. This is why a high-consumption home in a steep-tariff state can beat a similar home in a sunnier state with cheaper power.
Assuming a flat national generation figure. Output per kilowatt varies substantially with climate, and not only with sunshine hours — heat reduces module efficiency, so a hot bright location can underperform a mild one. Dust, shading and monsoon timing all move the annual number.
Forgetting the subsidy arrives later. You pay the installer in full and receive the assistance afterwards, so your money is committed before it is reimbursed. That is a cash-flow fact, not a cost, but it belongs in your planning — see how the subsidy is paid.
Net cost is only correct if the gross figure is complete. These items are commonly excluded from a headline quote and then appear later:
Ask for a written quotation with makes, models and a clear scope, then compare on a cost-per-watt basis. A wide spread between quotes usually reflects real differences in module and inverter grade, structure steel and coating, and what was quietly left out — not just margin.
Two levers matter far more than the brand of panel.
Shifting load into daylight. Because self-consumed units are worth more than exported ones, moving discretionary consumption into the middle of the day directly improves your return without changing the hardware. Running the washing machine, dishwasher, water pump, pool or irrigation pump on a timer during generating hours, pre-cooling rooms in the afternoon rather than cooling them from warm at night, and charging an electric vehicle at midday where possible all convert cheap exports into expensive avoided units.
Sizing to consumption rather than to roof area. Central assistance stops rising above 3 kW, so capacity beyond that is bought at full price and, on a modest consumption pattern, mostly produces low-value exports. A smaller system matched to your usage frequently pays back faster than a larger one — 3 kW vs 5 kW.
Neither lever costs anything to pull, which is why they are worth understanding before you choose equipment.
You enter your bill. We estimate system size, subsidy, monthly savings, net cost, payback, and a plain yes / maybe / not yet. That is for your decision — not a hard sales quote.
If the answer is yes or maybe, a local partner can visit the roof and give an exact number.
Two things make that quote easier to judge: knowing what annual generation per kW is realistic, so an inflated savings figure stands out, and the vetting checklist in choosing an installer. If a large part of your bill is electric water heating rather than cooling, also weigh a solar water heater against panels first. Two additions change the arithmetic sharply and are costed separately: battery storage, which is unsubsidised and buys outage cover rather than savings, and charging an electric car, which can push the sensible system size past the subsidy ceiling.
Take the gross quoted cost including everything the installation actually requires, subtract the central assistance you will receive, and divide that net cost by your realistic annual saving. Under about five years is usually attractive for a home with a solid bill, while beyond seven or eight years most households prefer to wait. The saving must be built on twelve months of bills rather than a peak-summer month.
Because a generated unit and a saved rupee are not the same thing. A unit you consume while the panels are producing avoids your full retail tariff, but a surplus unit exported to the grid earns only what the applicable tariff order allows, which is typically less. A household that is away all day exports a large share of its output and saves noticeably less than a household with daytime load on the same system.
Commonly excluded items include net-meter and processing charges from the distribution company, load enhancement if the capacity exceeds your sanctioned load, extra structure height or heavier specification for coastal and high-wind sites, civil and waterproofing work at anchor points, earthing and lightning protection, ongoing cleaning, interest if borrowing, and an inverter replacement at some point in the system's life.
Shift discretionary consumption into daylight hours, because self-consumed units are worth more than exported ones. Running pumps, washing machines and dishwashers on a timer during generating hours, pre-cooling rooms in the afternoon, and charging an electric vehicle at midday all convert low-value exports into avoided units at your full tariff. Sizing to your consumption rather than to available roof area has the same effect.
The case strengthens considerably once a monthly domestic bill is around Rs 2,500 or more, because solar removes your most expensive units first and a higher bill means a higher marginal rate. Below roughly Rs 1,000 to Rs 1,500 a month the units displaced are cheap and payback stretches past the point where the capital is worth committing, regardless of how good the roof or the sunshine is.
Related: Is solar worth it? · 3 kW price · Subsidy amounts
FAQ
Many banks and NBFCs offer solar loans; some schemes advertise collateral-free options. Terms change — ask your bank or installer. Loan interest affects true payback.
Panels degrade slowly (often ~0.5–0.7% per year in warranties). Year-1 savings are higher than year-20. Good vendors explain warranty and O&M.
Mostly cleaning dust and occasional checks. Budget a small annual amount; ask the installer what is included.
