Rooftop Solar & Subsidy Calculator
Estimate required solar panel kW capacity, rooftop area, PM Surya Ghar subsidy, and 25-year lifetime bill savings.
Consumption & Location Details
₹30,000 for 1kW | ₹60,000 for 2kW | ₹78,000 for 3kW & above.
Complete Guide to Rooftop Solar Sizing, PM Surya Ghar Subsidy & ROI Economics
Switching to residential on-grid rooftop solar systems eliminates up to 90% of household electricity bills. With the Government of India's PM Surya Ghar: Muft Bijli Yojana, homeowners receive direct cash subsidies credited to their bank accounts, reducing investment payback periods to under 3 years with 25-year panel performance warranties.
Solar Capacity & Rooftop Area Formulas
Standard solar photovoltaic (PV) generation mathematics in Indian tropical conditions:
Daily Electricity (Units) = System kW × 4.5 kWh/kW/day
Monthly Generation = System kW × 135 units
Shadow-Free Area = System kW × 100 to 120 sq. ft
Payback Period = Net Investment Cost ÷ Annual Bill Savings
PM Surya Ghar Yojana Subsidy Structure
Central Financial Assistance (CFA) subsidy slabs for residential consumers:
- • 1 kW System: ₹30,000 Direct Subsidy
- • 2 kW System: ₹60,000 Direct Subsidy
- • 3 kW & Above: ₹78,000 Maximum Capped Subsidy
- • Housing Societies (GHS/RWA): ₹18,000 per kW up to 500 kW
Residential Solar Rooftop Sizing & Subsidy Benchmark
| Solar Size | Roof Area (sq ft) | Monthly Generation | Est. System Cost | Govt Subsidy | Net Customer Cost |
|---|---|---|---|---|---|
| 1 kW | 100 sq. ft | 135 Units | ₹60,000 | ₹30,000 | ₹30,000 |
| 2 kW | 200 sq. ft | 270 Units | ₹1,20,000 | ₹60,000 | ₹60,000 |
| 3 kW | 300 sq. ft | 405 Units | ₹1,80,000 | ₹78,000 | ₹1,02,000 |
| 5 kW | 500 sq. ft | 675 Units | ₹3,00,000 | ₹78,000 | ₹2,22,000 |
Frequently Asked Questions (FAQ)
How does Net Metering work with on-grid rooftop solar?
A bi-directional net meter records both electricity imported from the DISCOM grid at night and surplus solar electricity exported to the grid during sunny afternoons. Your monthly bill is calculated strictly on the net units consumed (Import - Export).
How long is the typical lifespan and warranty of solar panels?
Tier-1 Mono PERC and TOPCon solar panels come with a 25 to 30-year linear performance warranty, ensuring at least 80% to 85% generation efficiency even after 25 years. Solar grid-tie inverters typically have a 5 to 10-year warranty.
How do I apply for the PM Surya Ghar government subsidy?
Register on the official National Portal for Rooftop Solar (pmsuryaghar.gov.in) with your electricity consumer number. Once your registered vendor installs the system and DISCOM inspects the net meter, the subsidy is directly transferred into your bank account via DBT within 30 days.