Pricing8 min read
3kW vs 5kW Solar System: Which Should You Buy?
The subsidy caps at 3kW, but the cheapest capacity you will ever buy is the extra kW added on day one. Here is how to decide between a 3kW and a 5kW system.
This is the most common fork in the road for Ahmedabad homeowners. A 3kW system captures the full ₹78,000 subsidy with the smallest outlay. A 5kW system costs more out of pocket but covers a bigger bill and future loads. The right answer depends on three things: your consumption, your roof, and your plans.
Side-by-side comparison
| 3kW class | 5kW class | |
|---|---|---|
| Suits monthly bill of | ~₹2,500 – ₹3,500 | ~₹4,500 – ₹6,500 |
| Shadow-free roof needed | ~200 – 250 sq ft | ~330 – 400 sq ft |
| Monthly generation | ~360 – 400 units | ~600 units |
| PM Surya Ghar subsidy | ₹78,000 (maximum) | ₹78,000 (same cap) |
| Extra capacity paid by you | None | ~2 kW at full price |
| Best for | Fan, light, fridge, 1 AC | Multiple ACs, EV charging, home office |
The subsidy cap changes the maths - but not the logic
Because PM Surya Ghar pays a maximum of ₹78,000 and reaches it at 3kW, every kW above 3 is fully self-funded. That makes the *net* per-kW cost of a 5kW system higher than a 3kW system. What people miss is the other side: labour, scaffolding, structure design, inverter headroom and DISCOM paperwork are already paid for on day one. Adding capacity later means repeating most of that.
Choose 3kW if…
- Your bill averages under about ₹3,500 a month and is stable.
- Your shadow-free roof area is limited to roughly 250 sq ft.
- You want the fastest payback and the smallest net outlay - around ₹86,000 net on our 3.3 kWp package.
- You run one AC seasonally rather than multiple units daily.
Choose 5kW if…
- Your bill regularly crosses ₹4,500 and climbs in summer.
- You have two or more ACs, a borewell pump, or plan an electric vehicle.
- You have 350+ sq ft of clear roof and want to use it once, properly.
- You expect household load to grow - a bigger inverter now avoids a second project later.
What we actually quote in between
Most Ahmedabad homes land between the two textbook sizes, which is why our packages are 3.3 kWp (₹86,000 net), 3.85 kWp (₹1,10,800 net) and 4.4 kWp (₹1,36,500 net) after the ₹78,000 subsidy. The 4.4 kWp system covers most two-AC households without the cost of a full 5kW build. Full component detail is on /pricing.
Size it from your bill, not from a brochure
Take your average monthly units from the last twelve bills, divide by roughly 120 units per kWp per month, and you have your target size. Our sizing-by-bill guide walks through it with examples, and the cost calculator does the arithmetic for you.
Still unsure? Send your last bill through /instant-quote. We will tell you honestly which size fits - including when the smaller one is the better buy.
Get a free quote for your home
Three fields, 30 seconds. We'll size your system, confirm your PM Surya Ghar subsidy tier and send a fixed written quotation - no site visit charge, no obligation.
Related reading
- 3kW Solar System Cost in Ahmedabad: Full Price Breakdown
A 3kW-class rooftop system is the most common residential size in Ahmedabad. Here is exactly what it costs, what the subsidy takes off, how much roof it needs and what it generates.
- 1kW to 5kW Solar System Price in Ahmedabad: Which Size Do You Need?
Not sure whether you need a 2kW, 3.3kW or 4.4kW system? Here is how to size solar for your Ahmedabad home based on your actual electricity bill, plus real pricing at each size.
- How Many Solar Panels Do You Need for a ₹3,000 Electricity Bill?
Forget panel counts - size from units. This guide converts your monthly bill into kW, panel count, roof area and net price for Ahmedabad homes.