Is Rooftop Solar Worth It?
Real payback periods, returns compared with a fixed deposit, 25-year savings, and the honest cases where rooftop solar doesn't make sense.
Rainbow Solar Energy Team
6 min read
Updated
In this article
Key takeaways
- For most Tamil Nadu homes using 300+ units a month, solar pays back in 3–5 years.
- That's a tax-free return of roughly 20–30% a year, far above a 7% fixed deposit.
- After payback you get 20+ years of nearly free daytime power.
- It's not worth it for very low users, heavily shaded roofs, or if you'll move out soon.
Rooftop solar is now one of the best financial decisions an Indian homeowner can make, but not for everyone. Here's how to tell if it's right for you.
The numbers: a typical Tamil Nadu home
| 3 kW system | 5 kW system | |
|---|---|---|
| Net cost after subsidy | ₹0.70 – ₹0.90 lakh | ₹1.75 – ₹2.10 lakh |
| Yearly savings (year 1) | ₹28,000 – ₹36,000 | ₹45,000 – ₹58,000 |
| Payback | 3 – 4 years | 4 – 5 years |
| Simple yearly return | ~28 – 35% | ~22 – 26% |
| 25-year savings (approx.) | ₹8 – 10 lakh | ₹13 – 16 lakh |
Indicative, for homes in higher tariff slabs. Returns rise as tariffs increase.
Solar vs a fixed deposit
Put ₹1 lakh in a fixed deposit at 7% and you earn about ₹7,000 a year, before tax. Put the same ₹1 lakh into a 3 kW system (after subsidy) and you save ₹28,000–36,000 a year on bills, tax-free, rising as tariffs rise. The catch: solar savings depend on you using the power, and the system needs basic care.
Get your own payback figure in seconds: our solar savings calculator uses your PIN code and the TNPDCL slab tariff.
When solar is clearly worth it
- Your bill is ₹2,000+ a month (₹4,000+ every two months).
- You run one or more ACs; see can you run an AC on solar.
- You own the home and plan to stay 5+ years.
- You have shadow-free roof space for the system you need.
When solar may not be worth it
- Very low use. In Tamil Nadu, the first 100 units every two months are free and the next slabs are cheap, so homes using under ~150 units a month save less and pay back slower.
- Heavy shade for most of the day.
- Weak or leaking roof that needs repair first.
- Moving soon, unless you can take the system with you or the buyer values it.
Benefits beyond the bill
- Protection from tariff hikes for 25 years.
- A cooler top floor: panels shade the roof slab.
- Higher property appeal through lower running costs.
- About 3.5 tonnes of CO₂ avoided each year with a 3 kW system.
Find out if solar is worth it for you
An honest assessment of your bill and roof. If solar doesn't make sense, we'll tell you.
Don't want to pay upfront? See solar loans and EMI options, where the EMI is often lower than your savings.
Written by our solar engineers and subsidy specialists, who design and install rooftop systems for homes, societies and businesses across Tamil Nadu. Figures are indicative and reviewed regularly; your free site survey gives exact numbers for your roof.
