Solar payback period in Johannesburg
Tony Lopes
Short answer: Payback is the system's cost divided by what it saves each year. On City Power's 2026/27 prepaid tariff, a well-sized home system typically pays for itself in about four to five years, and sooner for bigger users, because solar replaces the most expensive units first. High self-use and yearly tariff increases shorten payback. An oversized battery lengthens it.
Last updated November 2026. Rates checked October 2026.
Every solar quote comes with a payback claim. Here's how to check it for a solar installation in Johannesburg, with two worked examples on City Power's block tariff. For the broader question of whether solar still makes sense now that load shedding has stopped, read is solar still worth it in 2026?
How long does solar take to pay for itself in Johannesburg?
Payback in years = installed cost ÷ yearly saving.
The yearly saving is the solar units you actually use, valued at what they would have cost you. City Power charges more per unit the more you use each month: about R3.34 for the first 350 kWh, R3.80 from 350 to 500 kWh, and R4.37 above 500 kWh on Residential Prepaid High, including VAT. So the units solar replaces come off the top, at the highest rate. Our guide to City Power tariffs for 2026/27 has the details.
What do two worked examples look like?
| Example 1: three-bedroom home | Example 2: bigger home with a pool | |
|---|---|---|
| Monthly use before solar | 600 kWh (about R2,400) | 1,200 kWh (about R5,000) |
| System | 5 kW inverter, 5 kWp panels, 5 kWh battery | 8 kW inverter, 8 kWp panels, 15 kWh battery |
| Installed cost (assumed) | R95,000 | R180,000 |
| Solar used each month | About 470 kWh (70%) | About 920 kWh (85%) |
| Monthly saving | About R1,740 | About R3,860 |
| Yearly saving, year one | About R20,900 | About R46,300 |
| Simple payback | About 4.5 years | About 3.9 years |
The bigger home pays back faster because almost all its solar replaces units at R4.37, and it uses more of what the panels make. Solar production is based on about 4.5 kWh per kWp a day in Gauteng, as explained in what size solar system you need.
Do tariff increases shorten payback?
Yes. City Power's prices rose 8.63% in July 2026. If prices keep rising at around 9% a year, the saving grows each year too:
| Example 1 | Yearly saving | Saved so far |
|---|---|---|
| Year 1 | R20,900 | R20,900 |
| Year 2 | R22,800 | R43,700 |
| Year 3 | R24,800 | R68,500 |
| Year 4 | R27,100 | R95,600 |
So Example 1 pays back in about four years rather than four and a half.
What lengthens payback?
- Low self-use. If nobody is home and there's no battery, much of the solar goes unused or is exported for little credit.
- An oversized battery. Batteries cost more per rand saved than panels. Size for your evenings, not for load shedding.
- Registration costs. Registering with City Power can move you to postpaid with higher fixed charges. See SSEG registration in Johannesburg.
- Low usage. A household using under 350 kWh a month saves at the lowest block rate.
- Poor settings. A system still charging the battery from the grid every night wastes money. See load shifting.
Frequently Asked Questions
Does a battery lengthen payback?
A large one usually does. A battery sized for your evenings can shorten it, because it lets you use solar at night instead of buying top-block units. Size it to your evening use.
Do tariff increases shorten it?
Yes. Each yearly increase makes every solar unit worth more. At around 9% a year, a four-and-a-half-year payback comes down to about four.
What savings can I expect per month?
As a rough guide, each kWp of panels you fully use saves around R450 to R590 a month on City Power prepaid, depending on which block it replaces. Your own bill gives the real figure.
Where We Fit In
CleanVolts matches homes with vetted, registered CleanVolts Approved installers who size from your bills and show their payback working in writing. You contract the installer directly and they issue the Certificate of Compliance. Using CleanVolts costs you nothing, and if the installer pays us a referral fee, we tell you up front.
Sources: Business Day, 1 July 2026; EnergyBee metro tariff comparison.
