What is Solar ROI and Why Does It Matter?
Return on Investment (ROI) for solar is simply how long it takes for your energy savings to cover the cost of installation. After that point, every unit of electricity your panels generate is pure profit.
Real Data from 460+ Heliostrom Installations
| System Size | Install Cost (after subsidy) | Monthly Savings | Payback Period |
|---|---|---|---|
| 3 kW | ₹1,42,000 | ₹3,200–₹4,500 | 2.8–3.7 years |
| 5 kW | ₹2,02,000 | ₹5,000–₹6,500 | 2.6–3.4 years |
| 10 kW | ₹3,80,000 | ₹9,500–₹12,000 | 2.7–3.3 years |
| 25 kW | ₹8,50,000 | ₹20,000–₹28,000 | 2.6–3.5 years |
Factors That Affect Your Solar ROI
- Your current EB tariff (higher bills = faster ROI)
- Your roof's solar potential (south-facing, unshaded = best)
- System quality (Tier-1 panels degrade slower)
- Tamil Nadu's solar irradiance (excellent — 5.5 kWh/m²/day)
The 25-Year Picture
A typical 5 kW system in Chennai will generate approximately 7,500 units per year. Over 25 years (panel warranty period), that's 1,87,500 units of electricity — worth ₹11,25,000 at today's EB tariffs. Your net investment after subsidy is around ₹2,02,000. The math is compelling.
Tamil Nadu has some of India's best solar irradiance. Chennai receives ~5.5 peak sun hours per day — higher than Delhi (5.0) and Mumbai (4.7).
