Rooftop solar for a house: cost and subsidy

Look at the units (kWh) on your last 12 bills and take the monthly average. On a clear day, 1 kW of panels makes about 4–5.5 units. Over a year, with cloudy and monsoon days, the government puts a 3 kW system at over 300 units a month, so plan on about 100 units per kW. The scheme's own guide matches system size to use like this.

Shade matters more than size. A water tank, a neighbour's wall or a tree that shades the panels for part of the day cuts output sharply. Ask the installer for a shade check before you sign.

• On-grid: panels and an inverter, connected to the grid through a two-way (net) meter. No batteries. This is the cheapest kind and the one most homes choose. It switches off in a power cut, for safety.
• Hybrid: on-grid plus batteries, so some circuits keep running in a power cut. SolarSquare says an on-grid system costs less than half a hybrid one.
• Off-grid: batteries only, no grid. Mostly for farms and places without a reliable connection.

If power cuts are rare where you live, an on-grid system plus your existing inverter is usually enough. Check on the national portal whether the configuration you want qualifies for the subsidy before you choose.

Under PM Surya Ghar: Muft Bijli Yojana, the central subsidy is ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW. It is capped at ₹78,000 for 3 kW and above. Some states add their own: Delhi and Uttar Pradesh have each been reported to add up to ₹30,000 for a 3 kW system.

City prices for a 3 kW on-grid system ranged in October 2026 from about ₹2.15 lakh in Jaipur and Ahmedabad to about ₹2.6 lakh in Bengaluru, before subsidy. Our house calculator uses about ₹50,000 per kW after subsidy. For 3 kW that is ₹1.35–1.73 lakh. The city prices above, less the ₹78,000 subsidy, come to about ₹1.4–1.8 lakh, so the calculator is in line with them. For 5 kW it gives ₹2.25–2.9 lakh, at the bottom of the table, because the subsidy stops growing after 3 kW. Get quotes for a larger system.

Say your house uses about 350 units a month. A 3 kW system fits, needing about 300 sq ft of shadow-free terrace.

• Installed price, on-grid: about ₹2.0–2.6 lakh.
• Less the central subsidy of ₹78,000: you pay about ₹1.2–1.8 lakh in the end. You pay the full price first; the subsidy comes to your bank account after commissioning.
• Output: over 300 units a month, so most of your use is covered.
• Savings: if your top slab costs you about ₹7–8 a unit, 300 units saves roughly ₹2,100–2,400 a month, or ₹25,000–29,000 a year. Tariffs vary by state; use your own bill.
• Payback: ₹1.2–1.8 lakh ÷ ₹25,000–29,000 a year is about 4–7 years. The scheme asks for panels warranted to give at least 80% of their output at 25 years.

In the house calculator, 3 kW at about ₹50,000 per kW gives roughly ₹1.35–1.73 lakh, within this example's range. Use real quotes once you have them.

1. Register on the national portal with your electricity consumer number and mobile number.
2. Apply for rooftop solar. Your DISCOM checks feasibility for net metering.
3. Once the DISCOM approves, pick a registered vendor and get the system installed.
4. Submit the plant details on the portal and apply for the net meter.
5. The DISCOM inspects and fits a two-way meter. The portal then issues a commissioning certificate.
6. Submit your bank details and a cancelled cheque. The government's guide says the subsidy is paid within 30 days.

Net metering means the meter counts both ways. Units you send to the grid are set against units you take, and any surplus is settled at a rate your state regulator sets. Rules differ by state, so ask your DISCOM how surplus units are paid.

If you are building, plan for solar in the design. Ask your architect to keep the terrace clear on the south side, place the water tank where it won't shade the panels, and run a conduit from the terrace to the meter.

• Don't oversize. Beyond 3 kW the subsidy stops growing, and surplus units may be paid at less than you pay for power. Ask your DISCOM.
• Collateral-free loans at around 7% were announced for systems up to 3 kW. Ask your bank for the current rate and terms.
• Compare quotes on the same panel wattage and type, inverter brand, structure height and warranty.
• Ask who services the system and cleans the panels. Dust on the panels cuts output.
• A raised structure lets you use the terrace below. It costs more, so ask for it as a separate line.

A vendor registered on the national portal installs the system and handles the paperwork for the subsidy. For a new house, your MEP (services) engineer or electrical contractor can plan the conduit, earthing and meter position so the solar goes in cleanly later.