Rooftop Solar for Indian Homes: The Complete Guide

Rooftop solar has crossed a threshold in India: with falling panel prices, a government subsidy scheme, and net metering that lets you sell surplus back to the grid, a home solar system now pays for itself in a handful of years and then generates near-free power for two decades. But the details — on-grid versus off-grid, sizing, the subsidy, net metering, and choosing a good installer — decide whether you get those returns or a disappointing, oversized or badly-installed system. This guide is the complete, honest picture.

It sits under the residential electrical systems pillar and leads into the grid-tied vs off-grid guide and the solar battery storage guide.

The safety line. Solar design and installation — the panels, the inverter, the grid connection and the net meter — are done by a qualified, empanelled solar installer and a licensed electrician, to the module and inverter safety standards (IS 14286, IS 16221) and your DISCOM's rules. This guide helps you plan, size and judge; the rooftop wiring and grid interconnection are professional work.

How rooftop solar works

The system is simpler than it looks:

1. Solar panels (PV modules) on the roof turn sunlight into DC electricity.

2. A solar inverter converts that DC into 230 V AC your home can use, and (for grid systems) synchronises it with the grid.

3. Your home uses the solar power first; surplus flows to the grid through a net meter (which runs both ways), earning you credit.

4. When the sun isn't enough (night, cloud), the home draws from the grid (or a battery, in hybrid/off-grid systems) as normal.

So on a sunny day your home runs on solar and exports the excess; at night it imports from the grid, and the net meter tallies the difference. The panels are rated in kilowatts (kW); a typical Indian home system is 1–5 kW.

On-grid, off-grid or hybrid

The single biggest decision is the system type — covered in depth in the grid-tied vs off-grid guide, in brief:

• On-grid (grid-tied) — no battery; exports surplus to the grid and imports at night via net metering. Cheapest, most efficient, best payback — but does not work during a power cut (it shuts off for safety). The default where the grid is reliable and net metering is available.
• Off-grid — with batteries, no grid connection; runs independently. For places with no/poor grid; costlier because of batteries.
• Hybrid — grid-connected and battery-backed: exports surplus, and keeps running during outages. The best of both, at higher cost — increasingly popular where power cuts are common.

For a typical Indian home with a decent grid, on-grid gives the best return; hybrid adds outage backup for a premium.

Sizing a system

Solar is sized to your electricity consumption and your roof:

• By consumption: roughly, 1 kW of rooftop solar generates about 4 units (kWh) per day on average in much of India (~120 units/month). So to offset ~300 units/month you'd want roughly a 2.5–3 kW system. Size it to your usage, not bigger — oversizing wastes money (and net-metering rules may cap export).
• By roof: 1 kW needs roughly 7–10 m² (about 70–100 sq ft) of unshaded, well-oriented roof. So roof space can be the real limit.
• Shading and orientation: panels want unshaded, south-facing (in India) roof; shade from a tank, parapet or tree cuts output disproportionately.

Use the solar sizing calculator for a first estimate from your monthly units or roof area, then have an installer do a proper site assessment.

Cost, subsidy and payback

• Cost falls mainly on the panels, inverter and installation; it scales with system size, and prices have dropped a lot. Treat any figure as indicative and get quotes.
• Subsidy: the central PM Surya Ghar: Muft Bijli Yojana (launched 2024) provides a subsidy for residential rooftop solar through empanelled vendors and the national portal, on top of any state incentives — significantly improving payback for homes. Verify the current subsidy amounts, caps and eligibility on the official portal, as scheme terms change.
• Net metering turns your surplus into bill credit under your state DISCOM's net-metering policy (rules and caps vary by state).
• Payback: with the subsidy and net metering, residential payback is commonly a few years, after which the system generates for its ~25-year life — a genuinely strong return, though the exact numbers depend on your usage, tariff, state and system.

The honest headline: rooftop solar is now one of the best returns a homeowner can make on their roof — but the numbers depend on your consumption, tariff, state policy and a well-sized, well-installed system. Verify current subsidy and net-metering terms before committing.

Judging a good installation

• Empanelled, reputable installer registered under the subsidy scheme, with a proper site assessment, warranty and service.
• Quality panels and inverter conforming to standards (modules IS 14286; inverters IS 16221, grid-tied ones meeting anti-islanding IS 16169), with real efficiency and warranty figures.
• Right sizing to your consumption and roof — not an oversized system sold on commission.
• Sound mounting that withstands wind and monsoon and doesn't damage the roof/waterproofing.
• Proper grid interconnection and net meter approved by the DISCOM, with the right protection and earthing.
• Solar-ready wiring — if building, leave a conduit route from roof to the DB and space for the inverter (see the new-home design guide).

The one-line answer

Rooftop solar turns your roof into a power plant: panels make DC, an inverter converts it to AC your home uses first, and surplus flows to the grid through a net meter for credit — with the grid (or a battery, in hybrid systems) covering the night. Choose on-grid for the best payback where the grid is reliable, hybrid to also run through outages; size it to your consumption (~1 kW per ~4 units/day, ~7–10 m² of roof) rather than oversizing; and use the PM Surya Ghar subsidy and net metering — which now make residential payback a few years on a ~25-year asset. Verify current scheme terms, and use an empanelled installer to standards.

Where to go next

• The system-type choice: Grid-tied vs Off-grid vs Hybrid Solar.
• Storing solar energy: Solar Battery Storage.
• Charging an EV from solar: Home EV Charging Guide.
• Size a system: Solar Sizing Calculator.

References

• PM Surya Ghar: Muft Bijli Yojana (national rooftop solar scheme, 2024) — verify current terms: https://pmsuryaghar.gov.in/
• Ministry of New and Renewable Energy (MNRE), rooftop solar programme: https://mnre.gov.in/
• IS 14286 : 2010 (IEC 61215), Crystalline Silicon Terrestrial PV Modules — Design Qualification, Bureau of Indian Standards.
• IS 16221 (Parts 1–3, IEC 62109), Safety of Power Converters for Use in Photovoltaic Power Systems; IS 16169 : 2019, Utility-Interconnected PV Inverters — Islanding Prevention, BIS.
• Your State Electricity Regulatory Commission / DISCOM net-metering regulations (state-specific).

Costs, generation, subsidy and net-metering terms are indicative and vary by state, tariff, site and time; verify current scheme terms on the official portals. Design, installation and grid interconnection must be by a qualified installer and licensed electrician. Verify any standard's status via the BIS catalogue before relying on it.