Rooftop solar for Bihar homes — NBPDCL or SBPDCL, bill first

Bihar is one of India’s most populous states with a fast-growing urban belt around Patna — yet rooftop solar economics here depend on whether your DISCOM bill recovers net cost after PM Surya Ghar CFA, not on a generic “Bihar average” chart. Sealix advises; we are not NBPDCL, SBPDCL, or your installer. Start with the free home check.

Which DISCOM is on your bill?

Bihar domestic supply routes through two distribution companies. Read your bill header before selecting on pmsuryaghar.gov.in — wrong selection stalls feasibility.

• NBPDCL (North Bihar Power Distribution Company Ltd) — Muzaffarpur, Darbhanga, Purnia, Samastipur, and north / east Bihar districts
• SBPDCL (South Bihar Power Distribution Company Ltd) — Patna, Gaya, Bhagalpur, Munger, and south / central Bihar districts

Patna metro and most capital-region suburbs sit on SBPDCL. Border towns near UP or Jharkhand may show a different company — follow the bill, not the map pin.

PM Surya Ghar CFA in Bihar

Central residential CFA is commonly ₹30,000 / ₹60,000 / up to ₹78,000 for eligible 1–3 kW+ systems after commissioning. Bihar state top-ups, when announced, apply only to households meeting published eligibility at commissioning — do not assume a separate state cash amount unless an official Bihar energy department notice matches your date. Full walkthrough: PM Surya Ghar guide.

Monsoon and winter haze — plan honestly

June–September cloud cover across the Gangetic plain reduces daily generation versus dry-season peaks. November–January smog trims irradiance for weeks each year. Patna’s dense lanes and multi-storey neighbours add site-specific shade on top. Size from annual bill units, not a summer-only estimate or a Rajasthan comparison chart.

Bihar terrace realities

• Patna apartments — Boring Road, Bailey Road, and Kankarbagh societies often need RWA NOC on shared terraces — frequently the longest calendar item
• Independent houses — clearer roof rights in suburban belts like Danapur and Bihta, but overhead water tanks cast morning shade
• Flat RCC terraces — common across Bihar; confirm structural load capacity before signing a 5 kW quote on an older roof

Who should still run bill maths

• Homes with bills under ~₹1,500/month — payback may stretch even with CFA; see ₹1,500/month guide
• Flats on shared terraces with unclear NOC path
• Homes with heavy north-facing shade or multi-storey neighbours blocking south exposure

Net metering

Grid-tied rooftop solar needs a bi-directional net meter from your Bihar DISCOM. Settlement rules follow the BERC tariff order in force at commissioning — confirm live wording on your DISCOM portal before signing an installer quote. National explainer: net metering in India.

Sizing honesty

Many mid-to-high bill Bihar homes land near 3 kW to capture the full central CFA ceiling. Going to 5 kW adds capacity with no extra central CFA — see 3 kW vs 5 kW and ₹3,000/month bill guide.

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Uttar Pradesh · West Bengal · Odisha · Costs & savings · Areas.

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