The short answer
Home backup cost comes down to two things: how much you want to keep running, and for how long. A small setup that keeps lights, Wi-Fi and a few plugs alive is far cheaper than one that runs a whole home for hours. The main cost is the battery plus the inverter, then installation. Choosing an all-in-one battery with the inverter built in removes a separate purchase and a separate warranty, which usually lowers the total.
What makes up the cost
- Battery capacity (kWh): the biggest driver. Size it to your essential loads and how long you need them.
- Inverter: turns stored energy into usable 230 V AC. A standalone inverter is a separate cost; an all-in-one includes it.
- Installation: wiring, mounting, a Certificate of Compliance, and labour, which vary by site.
- Optional solar: panels are not required for backup, but they let you recharge for free and cut your bill. See adding a battery to existing solar.
For rough market pricing of the battery itself, see the solar battery price guide. We do not publish fixed system prices, because the right size depends on your home.
Size it to what you need
Most homes do not need to back up everything. A practical approach:
- Essentials only (lights, Wi-Fi, a TV, phone charging, a fridge): a compact battery such as the Sunpura S2400 covers a lot.
- Longer or larger (more appliances, longer runtime): step up to the S4800 or S6000, which expand as your needs grow.
Why the maths keeps improving
Even where backup is the reason you buy, the same battery cuts your bill day to day by storing cheaper energy and using it at peak tariff times. As tariffs rise, that saving grows. See Eskom tariffs and payback.
FAQ
Do I need solar for backup? No. A battery can charge from the grid at cheaper times and discharge during an outage or at peak. Solar makes it cheaper to run and adds daytime independence.
How long will backup last? It depends on your battery size and how much you run. Sizing to your essential loads gives the longest useful runtime. Ask us to size it.
Work out the right unit: see the range or request a quote.