A 3 BHK flat in Chennai with two or three air conditioners can easily run up a large bi-monthly EB bill. Rooftop solar can cut most of it, and as a flat owner you can still claim the full ₹78,000 PM Surya Ghar subsidy. The catch is that the terrace is shared, so the approvals matter as much as the panels.
- Size: most 3 BHK flats need a 3 kW system; 2 kW for light AC use, 4 kW for heavy use if roof space allows.
- Cost: roughly ₹2.2 lakh for 3 kW before subsidy, about ₹1.45 lakh after the ₹78,000 subsidy (indicative 2026 Chennai prices).
- Roof space: about 250–300 sq ft of shade-free terrace for 3 kW.
- Approvals: your own EB connection, a written NOC from your association for the terrace space, a registered PM Surya Ghar vendor, and TNPDCL net metering.
Can a flat owner install solar in Chennai?
Yes. An individual flat owner can install rooftop solar and claim the PM Surya Ghar subsidy if three things are true:
- You have your own domestic EB connection in your name, not a share of a common meter.
- You have the right to use part of the terrace, either written in your sale deed or given by your association in a formal NOC.
- Your sanctioned load can take the system. If your connection's sanctioned load is lower than the solar capacity you want, apply to TNPDCL for a load increase first.
The system is installed on the shared terrace, but it connects to your meter. The solar units it generates reduce your bill, and the subsidy goes to your bank account.
What size solar system does a 3 BHK flat need?
Size the system from your EB bill, not the number of rooms. Tamil Nadu bills domestic consumers every two months, so halve your bill's units to get your monthly usage. In Chennai, each 1 kW of panels produces roughly 110–120 units a month.
| Your 3 BHK's usage | Units per month | Units per bi-monthly bill | Suggested size |
|---|---|---|---|
| 1–2 ACs, used mainly at night | 200–300 | 400–600 | 2–3 kW |
| 2–3 ACs, regular use | 300–400 | 600–800 | 3 kW |
| 3+ ACs, work-from-home, EV charging | 400+ | 800+ | 4–5 kW (if terrace space allows) |
For most flat owners, 3 kW is the sweet spot. It is the size that earns the maximum ₹78,000 subsidy (there is no extra subsidy beyond 3 kW), and it fits in the terrace space associations typically allot to each flat. Get a closer figure from our solar system size calculator, or compare 3 kW vs 5 kW systems for a Chennai home.
Cost of solar for a 3 BHK flat in Chennai
Prices vary with panel brand, inverter, structure height and cable length. These indicative figures are based on published Chennai prices in 2026:
| System size | Approx. price before subsidy | PM Surya Ghar subsidy | Approx. price after subsidy |
|---|---|---|---|
| 2 kW | ₹1.9–2.0 lakh | ₹60,000 | ₹1.3–1.4 lakh |
| 3 kW | ₹2.1–2.3 lakh | ₹78,000 | ₹1.35–1.5 lakh |
| 4 kW | ₹2.5–2.7 lakh | ₹78,000 | ₹1.75–1.9 lakh |
Costs that are higher for flats than houses:
- Long cable runs: meters are usually in the ground-floor meter room, so the cable from the terrace can run several floors. Ask for the cable length in your quote.
- Elevated structures: raising panels above water tanks or the lift room, or to keep the terrace usable, costs more than a low structure.
- Waterproofing care: the structure must not damage the terrace's waterproofing. Ask how it is anchored.
See the full solar panel price list for Chennai (2026) and work out your subsidy with the Chennai solar subsidy calculator. Savings depend on your tariff slab; read how much solar saves a Chennai home.
How much terrace space does a 3 BHK flat need?
Plan for about 80–100 sq ft of shade-free terrace per kW:
| System size | Shade-free terrace needed |
|---|---|
| 2 kW | About 160–200 sq ft |
| 3 kW | About 250–300 sq ft |
| 4 kW | About 330–400 sq ft |
"Shade-free" is the key word. Water tanks, the lift machine room, parapet walls and neighbouring towers all cast shadows. An installer should do a shadow check before confirming your space. A small amount of shade on one panel can pull down the output of the whole string.
Approvals and documents for solar on a flat
From your apartment association
- A written NOC on the association's letterhead, signed by its office-bearers, stating the capacity (kW) and terrace area allotted to you.
- A resolution from the managing committee or general body approving rooftop solar and how terrace space is shared. A clear resolution prevents disputes later and is often asked for with the NOC.
- A marked terrace plan showing your panel area, cable route and access paths.
For PM Surya Ghar and TNPDCL
- Your EB consumer number, exactly as on your bill, and a recent bill
- Proof of ownership of the flat
- Aadhaar, and a bank account linked to it for the subsidy
- The association NOC
- A registered PM Surya Ghar vendor for Tamil Nadu, who installs DCR panels and files the installation details
- Net-meter application, inspection and commissioning by TNPDCL (formerly TANGEDCO)
Full checklist: documents required for the rooftop solar subsidy in Tamil Nadu. Before you sign, check that your installer is an approved PM Surya Ghar vendor, and read about TANGEDCO net-metering rules.
Your 3 options as a 3 BHK flat owner
For a building-wide plan, read our full guide to solar for apartments in Chennai.
Common problems in apartments, and how to solve them
| Problem | Fix |
|---|---|
| Not enough terrace space for every flat | Allot space by a formula agreed in a resolution (equal share, or by flat area), or go for a common-area system. |
| Shade from water tanks or the lift room | Use an elevated structure, or place panels away from shaded zones after a shadow check. |
| Long distance to the meter room | Plan the cable route early, use a proper cable tray, and price the cable in the quote. |
| Worries about terrace leaks | Use a structure fixing method that protects waterproofing, and get the installer's leak warranty in writing. |
| Some owners object | Share a written plan with panel area, access paths and safety measures before the general body meeting. |
| Sanctioned load too low | Apply to TNPDCL for a load increase before the solar application. |
Frequently asked questions
Can I install solar panels on my flat in Chennai?
Yes. If you have your own EB connection and your association gives you a written NOC for terrace space, you can install a rooftop system connected to your own meter and claim the PM Surya Ghar subsidy.
What size solar system is right for a 3 BHK flat?
Most 3 BHK flats in Chennai suit a 3 kW system, which produces roughly 330–360 units a month. Flats with light AC use can manage with 2 kW; heavy users may need 4 kW if terrace space allows.
How much does solar cost for a 3 BHK flat in Chennai?
A 3 kW system costs roughly ₹2.1–2.3 lakh before subsidy and about ₹1.35–1.5 lakh after the ₹78,000 PM Surya Ghar subsidy, based on indicative 2026 Chennai prices. Long cable runs or elevated structures can add to this.
Do I need permission from my apartment association?
Yes. The terrace is common property, so you need a written NOC from the association that states your capacity and allotted terrace area, ideally backed by a committee or general body resolution.
Can flat owners get the PM Surya Ghar subsidy?
Yes. An individual flat owner with their own domestic connection can claim up to ₹78,000. Associations can separately claim ₹18,000 per kW for common-area systems.
How much terrace space does a 3 kW system need?
About 250–300 sq ft of shade-free terrace. Water tanks, lift rooms and nearby towers can cast shade, so a shadow check is essential.
Will solar panels cause leaks on my terrace?
They should not if the structure is fixed correctly. Ask your installer how the structure is anchored, how waterproofing is protected, and whether they give a leak warranty in writing.
Planning solar for your flat?
Arka Solar Energy, a solar company in Chennai, surveys your terrace share, sizes the system from your EB bills, helps prepare the association NOC, and handles the PM Surya Ghar subsidy and TNPDCL net metering.
Prices are indicative and based on published Chennai prices as of September 2026; your quote depends on site conditions. Scheme rules can change, so confirm on pmsuryaghar.gov.in. Comparing installers? See the best residential solar companies in Chennai.