A neighbour of mine in Guwahati installed a 3 kW rooftop system last year mostly because his brother-in-law in Delhi kept saying his own bill had dropped to almost nothing. What he hadn’t worked out beforehand was how long it would actually take to get his money back, he just assumed “a few years” and went ahead. It turned out to be under 2.5 years, which surprised him more than the subsidy itself did. That’s the number most people skip when they’re deciding whether solar is worth it, not just the subsidy, but how fast the whole thing pays for itself. Here’s the full breakdown, and a calculator to work out your own numbers.
PM Surya Ghar subsidy slabs
The Central Financial Assistance under PM Surya Ghar: Muft Bijli Yojana is a flat rate per kW, capped once you cross 3 kW.
| System Size | Central Subsidy | System Cost (Approx) | Monthly Generation |
|---|---|---|---|
| 1 kW | ₹30,000 | ₹60,000 to ₹65,000 | ~120 units |
| 2 kW | ₹60,000 | ₹1,15,000 to ₹1,25,000 | ~240 units |
| 3 kW (Max Subsidy) | ₹78,000 | ₹1,65,000 to ₹1,80,000 | ~360 units |
| 5 kW | ₹78,000 (capped) | ₹2,70,000 to ₹2,95,000 | ~600 units |
Notice the subsidy stops growing after 3 kW, going bigger past that point means paying full price for the extra capacity, out of pocket.
Why 3 kW is the number most households land on
It isn’t a coincidence that 3 kW systems are the most common installation size. It’s the point where you get the full ₹78,000 subsidy without paying for capacity beyond it, and for a typical household running an APDCL bill in the ₹3,000 to ₹4,000 range, 3 kW roughly matches monthly consumption. Go smaller and you’re leaving subsidy on the table relative to your bill size, go bigger and the extra kW comes entirely at your own cost.
How the calculation works
- Compare your current monthly APDCL bill to your recommended solar capacity (roughly 1 kW per 100 sq ft of shade-free roof)
- Monthly Bill Savings = Current Bill − ₹120 (fixed meter charge, roughly all that remains after solar offset)
- Net Out-of-Pocket Cost = System Cost − Central Subsidy
- Payback Period = Net Out-of-Pocket Cost ÷ Annual Bill Savings
Now a smaller household on a 1 kW system:
My neighbour’s 3 kW system landed almost exactly on the first example, which is probably why he still brings up the payback number more often than the subsidy itself.
How to Use the Calculator
Step 1. Enter your current average monthly APDCL bill in rupees.
Step 2. Enter your available rooftop area in square feet (roughly 100 sq ft needed per kW). Step 3. Click “Calculate Solar Savings.”
Step 4. You’ll see your recommended capacity, subsidy amount, monthly bill savings, and payback period.
Applying for PM Surya Ghar, step by step
- National Portal Registration: register on pmsuryaghar.gov.in and select APDCL as your DISCOM
- Vendor Selection: choose an empanelled solar vendor registered for your district
- Technical Sanction: your vendor conducts a rooftop survey, and APDCL approves the Technical Feasibility Report
- Installation & Net Metering: panels are installed, then APDCL fits a bi-directional net meter
- Direct Subsidy Credit: once the net meter commissioning certificate is uploaded, the subsidy is credited to your bank account, typically within 30 to 45 days
Some things people ask us often
Kya Assam me solar rooftop ke liye low-interest bank loan milta hai?
Haan. SBI, PNB, aur Assam Gramin Vikash Bank jaise nationalized banks PM Surya Ghar ke andar bina collateral ke, 7% interest rate par ₹2 lakh tak ka solar loan dete hain.
Assam me baarish/monsoon ke dino me solar panel kaam karte hain?
Haan. Solar panels ambient sunlight se bhi power generate karte hain, monsoon ya baadalkaari dino me system apni peak capacity ka 40% se 60% power generate karta rehta hai.
APDCL Net Metering me surplus solar power ka kya hota hai?
Agar generation consumption se zyada hai, extra units APDCL grid me export ho jati hain, aur financial year ke end me AERC approved tariff par bill me credit ya payment milti hai.
Humara ghar joint family hai, chhat par jagah kaafi hai lekin bill do meter connections me split hai, mummy-papa ke naam alag aur humare naam alag, kya hum ek hi solar system laga sakte hain ya do alag applications lagegi?
Subsidy har electricity connection ke against milti hai, joint rooftop ke against nahi, to agar do alag meter numbers hain, technically do alag applications lagengi, chahe panel physically ek hi chhat par lage ho. Wiring aur net metering ko kaise split karna hai, ye vendor se pehle hi discuss kar lena behtar hoga, taaki dono connections ko sahi tarike se offset mile.
Solar panels ki warranty aur life kitni hoti hai?
Tier-1 solar panels ki performance warranty 25 saal hoti hai, aur solar inverters par 5 se 10 saal ki replacement warranty milti hai.
Is this an official government calculator?
No. This tool uses the published subsidy slabs and typical system costs to estimate your savings and payback period. Your actual quote depends on your empanelled vendor’s pricing and APDCL’s site-specific feasibility approval, this calculator gets you a close working estimate, not a final quotation.
Official Resources
Subsidy slabs, vendor lists, and net metering rules do get revised, so it’s worth checking these directly:
If you’re weighing whether to go ahead, the payback period usually settles the question faster than the subsidy amount does, most households with a mid-range APDCL bill recover their cost well within 3 years, and every year after that is straightforward savings.
