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Does home solar pay for itself in South Africa?

A solar system with panels can pay for itself, but slowly, and only if you count every cost. A battery without panels never lowers your bill. Here is how to do the sums honestly before you sign a quote.

Count the full cost, not only the quote

Add up everything over the life of the system:

• equipment and installation, including the electrical certificate of compliance (CoC);
• paperwork: commissioning, municipal registration and any meter change;
• a possible increase in your insurance premium;
• a yearly service by the installer, and panel cleaning;
• replacements: budget for the battery and the inverter to be replaced once in the life of the panels;
• finance charges, if you borrow.

Save energy first

Every kilowatt-hour you do not use saves money every month, with or without solar. The geyser is often a third or more of a home's electricity. A timer and a geyser blanket are the cheapest "power station" there is.

In the book's example, a timer and blanket costing about R1 200 cut a household's use from about 263 to about 200 kWh a month. That saved about R240 a month and paid for itself in five months.

How to work out the payback

1. Estimate the solar energy your panels produce in a day.
2. Estimate the share you actually use in the home, directly or through the battery. A well-designed system uses most of it.
3. Multiply the energy used a day by 365 to get the energy saved a year.
4. Multiply by your price per kWh to get the rand saved a year.
5. Divide the system cost by the rand saved a year. That is the simple payback in years.

A worked example

A retired couple's system produces about 12.4 kWh a day, and they use about 85% of it.

• Energy used in the home: about 10.5 kWh a day, or about 3 830 kWh a year.
• At R3.80 a kWh, that saves about R14 550 a year.
• The system cost R140 000, so the simple payback is about 9.6 years.
• If tariffs rise about 10% a year, the savings add up to the cost after about 7 years.

Against that, count a yearly service of about R1 500, a battery and inverter that will probably need replacing in 10 to 15 years, and the interest the money would have earned in the bank. Nobody can promise future tariffs, so work it out both ways.

Backup without panels does not save money

A router UPS, a power station, or an inverter and battery without panels only store mains power, with small losses. Value them by what they protect: a child's studies, the food in the freezer, a business's income, your security and a night's sleep.

A small business that loses about R800 of trade on each day without power can find that a backup system protects its cost in months, not years.

This article is based on Chapter 12 of Solar Backup Power for Your Home. The figures are the book's worked examples from 2026, so use your own tariff and quote.