Rooftop Solar & PM Surya Ghar Calculator
Calculate optimal rooftop solar capacity (kW), panel counts, shadow-free roof area, Central Govt subsidy, and payback period.
Frequently Asked Questions
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Continue with another electricity or backup-planning tool.
Reference official efficiency and safety guidance from Bureau of Energy Efficiency and standards information from Bureau of Indian Standards.
Calculation Assumptions & Safety
Calculations are planning estimates using the displayed inputs and assumptions, not certified designs or verified provider bills. Actual runtime, generation, cost and wire requirements vary with equipment, installation and operating conditions. Confirm manufacturer specifications and current provider rules. Have a qualified electrician review wiring and backup installations.
Solar capacity for 300 units of monthly electricity
At an illustrative 4.5 equivalent sun hours per day and 75% system performance, 300 kWh ÷ (30 × 4.5 × 0.75) ≈ 2.96 kW of nominal solar capacity. Actual yield depends on roof orientation, location, shading and season.
How the calculation works
Solar kW ≈ monthly electricity kWh ÷ (days × equivalent sun hours × performance factor). Installation prices, exports and subsidy eligibility are separate assumptions.
Compare household scenarios
- 200 units/month: approx 1.98 kW at stated assumptions
- 300 units/month: approx 2.96 kW
- 500 units/month: approx 4.94 kW
Common questions
- How many panels for 300 units per month?
- An illustrative 3 kW system built from six 540 W modules has 3.24 kW of nominal DC capacity. Confirm actual module models, roof geometry and generation assumptions.
- Is a PM Surya Ghar subsidy guaranteed?
- No. Assistance depends on the latest scheme requirements, installation and eligibility. Check the official programme before deducting a subsidy from the estimate.
Before relying on a concession, read the state-wise electricity benefit conditions. Compare Tamil Nadu bill and solar assistance, Rajasthan’s solar-linked programme and Chhattisgarh M-URJA and solar support only for the relevant location.