Why Solar Makes Sense for a New Construction
When you're building a new house from scratch, installing solar panels is cheapest and easiest at construction time — roof structure can be designed to accommodate panels, wiring routed cleanly from the start.
Chennai has an average of 300+ sunny days per year and 5.5–6 peak sun hours daily — among the best solar resource in India.
System Sizing for a Typical House
For a 800–1,000 sq ft house with: 3 fans, 5 LED lights, 1 TV, 1 refrigerator, 1 washing machine, 1 AC (8 hours): recommended system: 3kW solar + 1 inverter battery backup.
Daily generation: approximately 13–15 units. Monthly: 400–450 units. TNEB average consumption for this household: 300–350 units/month. Net result: net-metering surplus in most months, credits your electricity account.
2025 Cost and Subsidy
**System cost (3kW):** ₹1.8–2.4 lakhs for quality branded panels (Waaree, Adani, Vikram Solar) with reputed installer.
**PM Surya Ghar Muft Bijli Scheme subsidy (2025):** The central government scheme offers: ₹30,000 subsidy for 1kW, ₹60,000 for 2kW, ₹78,000 for 3kW. Additional TANGEDCO subsidy (varies; check current portal at tangedco.gov.in/solarrooftop).
**Net 3kW system cost after subsidy:** Approximately ₹1.0–1.5 lakhs.
Payback Calculation
Annual TNEB bill saving: 400 units/month × 12 = 4,800 units × ₹7/unit average = ₹33,600/year. Additionally, net-metered surplus units credited at TANGEDCO buy-back rate.
At ₹33,600/year saving on a ₹1.2 lakh net investment: payback in 3.5 years. System life: 25 years. Net lifetime saving: ₹8+ lakhs.
How to Get the Subsidy
Apply online through the PM Surya Ghar portal (pmsuryaghar.gov.in). Get DISCOM (TANGEDCO) approval before installation. Only approved vendors eligible for subsidy. Installation and inspection, then subsidy disbursed directly to bank account. Entire process typically 6–10 weeks.