Solar and inverter payback calculator
Enter your quote, the grid electricity the system will replace and your tariff. See the year it pays for itself and the savings over its life.
Your details
Pays for itself in
5 yr 8 mo
Then saves about R703 141 by year 20
- Saving in year 1
- R18 554.94
- Saving per month, year 1
- R1 546.25
How we worked it out
- System costR120 000.00
- Grid electricity replaced per year5 400.0 kWh
- Saving in year 1R18 554.94
kWh × 3.44 rand per kWh
- Running costs per yearR1 500.00
- Net position after 20 yearsR703 140.82
Tariff rising 9.0% a year, output falling 0.5% a year
- This ignores the cost of borrowing and any income from feeding power back to the grid. Backup during load-shedding has value that is not counted here.
Year-by-year savings
| Year | Saving | Costs | Running total |
|---|---|---|---|
| 1 | R18 555 | R1 500 | −R102 945 |
| 2 | R20 124 | R1 500 | −R84 321 |
| 3 | R21 825 | R1 500 | −R63 996 |
| 4 | R23 671 | R1 500 | −R41 826 |
| 5 | R25 672 | R1 500 | −R17 654 |
| 6 | R27 842 | R1 500 | R8 689 |
| 7 | R30 197 | R1 500 | R37 385 |
| 8 | R32 750 | R1 500 | R68 635 |
| 9 | R35 519 | R1 500 | R102 654 |
| 10 | R38 522 | R41 500 | R99 675 |
| 11 | R41 779 | R1 500 | R139 954 |
| 12 | R45 311 | R1 500 | R183 765 |
| 13 | R49 142 | R1 500 | R231 407 |
| 14 | R53 297 | R1 500 | R283 205 |
| 15 | R57 803 | R1 500 | R339 508 |
| 16 | R62 691 | R1 500 | R400 699 |
| 17 | R67 991 | R1 500 | R467 190 |
| 18 | R73 740 | R1 500 | R539 430 |
| 19 | R79 975 | R1 500 | R617 904 |
| 20 | R86 736 | R1 500 | R703 141 |
How the payback is worked out
- Saving each year = grid kWh replaced × your tariff, with the tariff rising by your chosen percentage each year and panel output falling by 0.5% a year.
- Costs each year = maintenance and insurance, plus a battery replacement in the years it falls due.
- Payback is the point where total savings minus costs equal what you paid.
Getting the "kWh replaced" figure right
This is the most important input. Only count solar power you actually use or store and use later. Power produced while nobody is home and the battery is full is wasted unless you can feed it into the grid. Your installer should give you an estimate based on your past bills.
Frequently asked questions
How long does solar take to pay for itself in South Africa?
It depends on the system cost, how much of the power you actually use, your tariff and how fast tariffs rise. Enter your installer's quote and expected output to see your own payback period.
Do batteries make solar pay back faster?
Usually not on cost alone: batteries add to the price and need replacing. Their value is backup during load-shedding and outages, which this calculator does not put a rand value on.
What tariff increase should I assume?
That is an assumption, not a fact. For reference, NERSA approved an average 8.76% increase for Eskom direct customers from 1 April 2026 and 9.01% for municipalities from 1 July 2026. Try a few values to see how sensitive your payback is.
Can I sell power back to the grid?
Some municipalities allow registered systems to feed in, and pay a credit. It varies widely, so it is left out here; it would shorten your payback.