How many kW do I need?
It depends on your units. In Tamil Nadu, 1 kW generates roughly 110–125 units a month. Most homes size the system to bring grid usage down to the 200 free-unit band — use the calculator above for your number, and we confirm it on a site visit.
What is an on-grid solar system?
A system connected to the TNPDCL grid through a net meter. Your home uses solar power first; surplus goes to the grid, and you draw from the grid at night. There are no batteries.
What happens when there is a power cut?
An on-grid inverter switches off automatically during a grid outage so no power flows into lines being repaired. If you need backup, ask about a hybrid system with batteries.
How does net metering work?
A bi-directional meter records units you import and export. Your bill is based on the difference, as per current TNERC and TNPDCL rules.
How much subsidy can I get?
Central subsidy is up to ₹78,000 (₹30,000 for 1 kW, ₹60,000 for 2 kW, ₹78,000 for 3 kW and above). Tamil Nadu has announced up to ₹22,000 extra for eligible applicants. Final amounts depend on eligibility and approval.
Who is eligible for subsidy?
Residential consumers with their own connection and suitable roof, who have not claimed rooftop solar subsidy before, installing DCR panels through a registered vendor. Commercial buildings are not eligible.
How long does installation take?
On-site work for a home is usually 1–3 days. The full process including portal approval, TNPDCL inspection and net meter can take a few weeks.
What roof area is required?
Roughly 80–100 sq ft of shade-free area per kW. A 3 kW system typically needs about 250–300 sq ft. Elevated structures can help on busy terraces.
What happens during cloudy weather?
Generation drops but doesn't stop. The grid covers the gap automatically. Our estimates already use yearly averages that include cloudy and monsoon days.
What maintenance is required?
Rinse the panels with plain water every 2–4 weeks (more often in dusty areas), and have an annual check of connections, earthing and the inverter.
How long do solar panels last?
Good panels work for 25 years or more, slowly losing about 0.5% output per year. The panel maker's performance warranty covers this — we list the exact terms in your quote.
What warranty is provided?
Panels and inverters carry manufacturer warranties, and installation workmanship is covered separately. Exact terms vary by component and are written into your quote.
What happens if the inverter fails?
You keep receiving grid power, so your home isn't affected. We diagnose the fault and handle the warranty claim with the manufacturer.
Can I expand the system later?
Often yes, if roof space, inverter capacity and your sanctioned load allow. Subsidy is one-time, so tell us about future plans (like an AC) before we size your system.
Is solar suitable for apartments?
An individual flat usually can't install unless it has roof rights. Residential associations can install solar for common areas; separate provisions apply. Ask us to check your building.
How do I know which panel and inverter to choose?
Look for DCR panels from established makers, a reputable inverter with local service, and clear warranties. Use the component guide above and ask every installer to list models in writing.
How does Sunfarm support customers after installation?
We walk you through the system at handover, set up monitoring, and remain your contact for generation checks, maintenance and warranty claims.
