Quick answer: take your average monthly units from the bill and divide by 135 — that is roughly the kW you need, because 1 kW of solar makes about 135 units a month. Example: about 405 units a month (a bill of roughly ₹2,835 at ₹7/unit) → 3 kW. Try it instantly on our savings calculator.
Sahi size chunna sabse zaroori faisla hai. Too small and the bill stays; too big and you pay for units you can't use. Here's the simple way to get it right.
Step 1: Find your monthly units
Look at the units consumed on your electricity bill — not just the rupee amount, because the bill also has fixed charges and taxes. Summer and winter use are very different, so take the average of the last 12 months if you can.
No units on hand? A rough guide: monthly bill ÷ ₹7 per unit ≈ units per month.
Step 2: Convert units to kW
kW needed ≈ monthly units ÷ 135
| Monthly units | Suitable system |
|---|---|
| Up to 150 | 1–2 kW |
| 150–300 | 2–3 kW |
| Above 300 | 3 kW or more |
Each kW makes about 135 units a month in a typical Haryana roof with good sun. A south-facing roof without shade does best.
Why 3 kW is the sweet spot for homes
PM Surya Ghar gives ₹30,000 for 1 kW, ₹60,000 for 2 kW and the full ₹78,000 at 3 kW. Above 3 kW the subsidy stays at ₹78,000. So if your use is close to 3 kW, going to 3 kW gets you the full subsidy and about 405 units a month.
Roof space: will it fit?
Plan about 100 sq ft of shadow-free roof per kW. A 3 kW system needs roughly 300 sq ft. Water tanks, stair rooms and trees can cast shade — we place the panels around them, or use an elevated structure.
Sanctioned load matters
Your solar size is normally matched to the sanctioned load on your connection. If you want a bigger system than your load allows, a load extension with the DISCOM comes first. We check this during the survey.
Plan for tomorrow, not just today
Planning an AC, an induction cooktop or an electric scooter? Add those units now. It is cheaper to size right at the start than to add panels later.
Quick examples
- Bill of about ₹2,835 a month (≈ 405 units at ₹7) → 3 kW, subsidy ₹78,000, price after subsidy about ₹1,02,000
- Much smaller bill, around half of that → 1–2 kW is usually enough
- Shop or bigger home with high summer use → 4–5 kW or more (the subsidy for homes stays ₹78,000)
Get your exact size from your own bill on the savings calculator, check the EMI on the EMI calculator, or book a free site survey — our engineer checks roof, shade and load and gives the size in writing.
