Rooftop solar in India — payback math after PM Surya Ghar

Quick frame: PM Surya Ghar Yojana launched Feb 2024 — 30-40% subsidy on residential rooftop solar (up to 3 kW = ₹78,000). Indian conditions average 4 kWh per kW per day — a 3 kW system generates ~360 kWh/month. At ₹8/unit tariff, that's ₹2,880/month savings = ₹35k/year. Net system cost after subsidy: ~₹1.4-1.8 lakh. Payback in 4-6 years; panels last 25-30. Easy ROI for homeowners.

How PM Surya Ghar works

• Up to 1 kW: ₹30,000 subsidy
• Up to 2 kW: ₹60,000
• Up to 3 kW: ₹78,000
• Beyond 3 kW: No additional subsidy (cap at 3 kW for full benefit)

Apply on pmsuryaghar.gov.in. Discom approval, vendor empanelment, installation, commissioning. Subsidy disbursed to vendor within 30 days.

Cost breakdown

For 3 kW system:

• Panels (10×300W): ₹60,000
• Inverter (3 kW string inverter): ₹35,000
• Structure, cables, wiring: ₹25,000
• Net metering installation: ₹10,000
• Installation labour: ₹15,000
• Other (taxes, transport): ₹15,000
• Gross: ₹1,60,000
• Subsidy (PM Surya Ghar): -₹78,000
• Net: ₹82,000

Use the Solar Panel ROI Calculator for your specific case.

Annual savings

3 kW × 4 kWh/kW/day × 365 = 4,380 kWh/year. At ₹8/unit = ₹35,000/year.

Payback

₹82,000 / ₹35,000 = 2.3 years. After subsidy, payback is fast.

Even at ₹5/unit (cheaper states): ₹82,000 / ₹21,900 = 3.7 years. Still excellent.

When NOT to install

• Apartment without dedicated rooftop access (society politics)
• Roof shaded by trees / buildings > 30%
• Sub-tropical / extreme heat without ventilation under panels (rare in India)
• Selling property in < 2 years

Net metering basics

The grid acts as your "battery". Excess generation (afternoon) gets sold to grid. At night you draw from grid. Bill = (units consumed - units fed back) × tariff.

If you generate more than you consume annually, some discoms pay you the average price (₹2.50-4.50/unit). Most don't — net is reset to zero each year.

FAQ

Q. Can I install solar in a flat? A. Need building society approval. Some societies allow individual flats; others require centralised solar (shared cost). Discuss with your secretary.

Q. Battery storage cost? A. Doubles total cost. Most homes don't need it (grid-tied is enough). Consider battery only if power cuts are severe.

Q. Maintenance? A. Annual cleaning ₹2-3k. Inverter replacement at year 10-12 (~₹40k). Panels themselves last 25-30 years with minor efficiency degradation.

Q. Tax benefits? A. None directly for residential. Commercial / industrial gets 80% accelerated depreciation. PM Surya Ghar is the main residential benefit.