Solar / Inverter ROI CalculatorBill savings + downtime avoided + productivity preserved — combined into one payback number.

System

System costR 180 000

System lifespan15 years

PV offset of grid bill70%

Monthly electricity billR 3 500

Daily outage hours2 h

Generator fuel cost / hrR 120

WFH productivity / hrR 400

Your hourly value during outages — set to 0 if outages don't cost you income.

WFH dependency60%

Fuel inflation18%

Forecast >18% for 2026 in SA.

Electricity inflation13%

Verdict

Payback period

Never

Lifetime ROI

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Year-1 monthly saving

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