Blog · ROI Analysis
Solar ROI by System Size: 3kW, 5kW, 10kW Compared
Which solar system size gives the best payback for your Tamil Nadu home? Compare costs, subsidies, and monthly savings.
3kW Solar System
- Ideal for: 2-3 bedroom homes, monthly bill ₹2,000-3,500
- Cost (after subsidy): ₹1.25L-1.5L (subsidy ~₹54k)
- Generation: 12-15 units/day (~360-450 units/month)
- Monthly savings: ₹2,500-3,500
- Payback: 3.5-4 years
- 25-year returns: ₹7.5L-10L after paying back investment
5kW Solar System
- Ideal for: 3-4 bedroom homes with AC, monthly bill ₹4,000-6,000
- Cost (after subsidy): ₹2L-2.5L (subsidy ~₹78k)
- Generation: 20-25 units/day (~600-750 units/month)
- Monthly savings: ₹4,000-6,000
- Payback: 4-4.5 years
- 25-year returns: ₹12L-15L after ROI
10kW Solar System
- Ideal for: Large homes, villas, small shops, monthly bill ₹7,000+
- Cost (after subsidy): ₹4L-5L (subsidy limited on higher capacity)
- Generation: 40-50 units/day (~1,200-1,500 units/month)
- Monthly savings: ₹8,000-12,000
- Payback: 4-5 years
- 25-year returns: ₹24L-30L after ROI
Key Factors That Impact ROI
- Your current TANGEDCO tariff slab (higher slab = faster payback)
- Roof orientation and shading (south-facing, zero-shade is ideal)
- Panel quality (Tier-1 mono PERC gives 18-20% better output)
- Net metering approval and grid stability in your area
- Future tariff hikes (solar locks in low energy costs)
FAQ
- 3kW payback? Typically 3.5-4 years with ~₹54k subsidy and ₹2,500-3,500/month savings.
- 5kW enough? Yes, covers most 3-4 bedroom homes; generates 20-25 units daily in Tamil Nadu.
- 10kW worth it? Ideal for ₹6,000+ bills; net metering credits excess generation; 4-5 year ROI.