"What size do I need for my flat?" is one of the most common questions — and the honest answer is: it depends far more on your bill than your home's BHK label. Still, typical usage patterns give a useful starting range. Here's the practical version.
Typical ranges by home size
| Home | Typical monthly bill | Rough system size |
|---|---|---|
| 1BHK / small household, light AC use | ₹1,000–1,800 | 1–1.5 kW |
| 2BHK, moderate AC use | ₹2,000–3,000 | 2–2.5 kW |
| 3BHK, regular AC use (1–2 units) | ₹3,000–4,500 | 3–3.5 kW |
| Larger home / multiple ACs, heavy use | ₹5,000+ | 4–5+ kW |
Why 3 kW is the most common recommendation
A 3 kW system suits a lot of 3BHK households in India, and it happens to be the size that collects the full ₹78,000 PM Surya Ghar subsidy — the central subsidy is capped at 3 kW, so there's no extra central subsidy for sizing up further. That combination of "fits typical usage" and "collects the max subsidy" is why 3 kW shows up so often in vendor recommendations. It's a genuinely sensible default for many homes — just don't treat it as automatic.
What actually shifts you up or down from the table
- Number and usage of air conditioners — the single biggest swing factor in Indian homes.
- Work-from-home patterns — more daytime usage means more of your own solar gets self-consumed rather than exported.
- Upcoming changes — a planned EV or a new AC unit is worth sizing for now, if you're fairly confident it's coming.
- Roof space — about 100 sq ft per kW; a 3 kW system needs roughly 300 sq ft unshaded.
Get your exact size, not just a BHK guess
See your system size, cost after subsidy, and payback period in 30 seconds — with every assumption shown.
The honest recommendation
Use the table above as a starting conversation with yourself, then confirm with your actual electricity bill — it's a far better predictor than square footage or bedroom count. Two minutes with the calculator will give you a size, cost, and payback period specific to your home, not a generic bracket.
A note on the numbers: figures here are typical ranges as of June 2026 and change often. The PM Surya Ghar subsidy structure, your state's top-up, per-kW prices and electricity tariffs all vary — always confirm current rates on the official portal (pmsuryaghar.gov.in) and get written quotes before you buy. This is planning information, not financial advice.