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What size solar system do I need?

Built by the Solar Samachar editorial desk · Figures updated for 2026

In shortEnter your monthly electricity bill. We estimate your usage, the kW you need, the cost after PM Surya Ghar subsidy, your yearly savings and payback — using typical 2026 India numbers.

Average monthly bill (₹) Your tariff (₹/unit)

—Recommended size

—Monthly units used

—Net cost after subsidy

—Payback period

Estimated yearly savings: — · Est. subsidy: — · Roof needed: —

Assumes ~4 units/day per kW, ~₹65,000/kW installed (indicative 2026), and PM Surya Ghar central subsidy (max ₹78,000). Net metering keeps daytime surplus valuable. Estimates only — get quotes to confirm.

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How we work it out

Units used = monthly bill ÷ your tariff.
Size (kW) = monthly units ÷ ~120 (since 1 kW ≈ 4 units/day ≈ 120 units/month), rounded to a practical size.
Cost ≈ ₹65,000 × kW; subsidy per PM Surya Ghar (₹30k/kW first 2 kW + ₹18k for 3rd, max ₹78k).
Savings ≈ the grid units you no longer buy; payback = net cost ÷ yearly savings.

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An estimate is a great start — get 3 free, no-obligation quotes from vetted installers near you to see your actual price and subsidy.

FAQs

What size solar system do I need in India?

As a rule of thumb, roughly 1 kW of rooftop solar generates about 4 units a day (~120 units a month). Divide your monthly units by ~120 to get the kW you need to offset most of your bill.

How much roof area does solar need?

About 70–100 sq ft of shadow-free roof per kW. So a 3 kW system needs roughly 250–300 sq ft.

What is the payback period for solar in India?

For a subsidised residential rooftop system, payback is typically 3–4 years, after which the electricity is effectively free for the system’s ~25-year life.

Is the estimate exact?

No — it’s a planning estimate using typical 2026 figures. Your tariff, sunlight, roof and quotes vary, so always confirm with an installer.

Sources: PM Surya Ghar / MNRE (pmsuryaghar.gov.in) · Electricity (Rights of Consumers) Rules, 2020

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These are planning estimates for 2026 — your actual system, tariff, sunlight and quotes will vary. Always confirm with an installer.