Why 3 kW Solar Is Bihar’s Most Popular Choice
For an average Indian household with 2 to 3 air conditioners, a refrigerator, water pump, and standard lighting, a 3 kW On-Grid Solar System represents the sweet spot between upfront investment and maximum return. Under the central government's PM Surya Ghar: Muft Bijli Yojana, systems up to 3 kW receive the highest proportion of direct government financial assistance.
3 kW Solar System Cost Breakdown in Bihar
The gross benchmark cost of a standard 3 kW on-grid solar system with Mono PERC / TOPCon bifacial modules, a smart string inverter, galvanized mounting structure, ACDB/DCDB boxes, and copper chemical earthing ranges between ₹1,55,000 and ₹1,75,000 (before subsidy), depending on structural elevation and cable length requirements.
Indicative 3 kW Price Summary (August 2026)
- Gross Turnkey System Cost: ₹1,65,000 (Approx.)
- PM Surya Ghar Central Subsidy: ₹78,000 (Direct DBT to bank account)
- Effective Net Customer Investment: ₹87,000
PM Surya Ghar Subsidy for 3 kW in Bihar
Under the national PM Surya Ghar framework, rooftop solar subsidies are structured as follows:
- First 1 kW: ₹30,000
- Second 1 kW (2 kW total): ₹60,000 (₹30k per kW)
- Third 1 kW (3 kW total): ₹78,000 (maximum cap for residential rooftop systems)
This means residential consumers in Bihar installing a 3 kW system qualify for the full ₹78,000 subsidy transferred directly to their Aadhaar-linked bank account post-inspection.
Power Generation & Monthly Savings
In Bihar, which receives an average of 300 clear sunny days annually, a 3 kW solar array generates approximately 360 to 400 units (kWh) of electricity per month (approx. 4,500 units annually).
At current SBPDCL/NBPDCL domestic tariff rates of ~₹6.50 to ₹7.50 per unit, this equates to monthly savings of ₹2,400 to ₹3,000. Over a 25-year panel lifecycle, total cumulative savings exceed ₹7.5 Lakhs.
Roof Area Required for 3 kW
Modern high-efficiency 550W mono PERC modules require approximately 250 to 300 sq. ft. of shadow-free rooftop space. High-rise elevated galvanized structures can also be installed if you wish to retain complete usable terrace area underneath.
NBPDCL / SBPDCL Net-Metering Process
Net metering allows surplus electricity generated during peak afternoon hours to be exported to the Bihar state power grid. The electricity department replaces your existing meter with a bi-directional smart net meter that tracks units imported versus exported.
Is 3 kW Right for Your Home?
If your monthly electricity bill is between ₹2,500 and ₹4,500, a 3 kW rooftop solar system provides near 100% bill offset with an estimated payback period of just 2.8 to 3.2 years.