Payback period is the single number most customers actually care about — here's how to calculate it honestly.
The basic formula
- Net cost = system cost minus subsidy (see PM Surya Ghar).
- Annual savings = units generated × your tariff rate.
- Payback = net cost ÷ annual savings.
"A 3kW residential system in India typically pays back in 3.5–5 years, then saves for 20+ more."
| System | Typical payback |
|---|---|
| 3 kW | ~4 years |
| 5 kW | ~4.5 years |
Payback estimates only hold if the system is sized correctly — see how many panels you actually need and factor in long-term degradation.