Hybrid, off-grid or grid-tie: which inverter?
What each kind of inverter does, and which one keeps the lights on in a power cut.
An inverter turns the direct current (DC) from panels or a battery into the 230 V alternating current (AC) your home uses. There are three main kinds, and the difference matters most in a power cut.
Grid-tie
Panels feed the home first. Surplus can go to the grid only if your municipality (or Eskom) has approved export and fitted a suitable meter; otherwise the inverter must be set to block export ("zero export"). There is no battery, so when the grid goes down the inverter must switch off: it may not feed a dead line while people work on it. A grid-tie system saves money on sunny days but gives no backup in a power cut.
Off-grid
Panels and a battery run the home without the grid. Many off-grid units can take grid or generator power to charge the battery, but they don't send power back to the grid. If an off-grid inverter is also wired to the grid supply, the grid rules can still apply: the City of Cape Town, for example, now treats all new solar and battery systems as grid-connected and no longer accepts new off-grid applications, and Eskom exempts only systems that are fully independent of its network.
Hybrid
Panels, a battery and the grid together. The hybrid inverter runs the home from the sun first, keeps the battery charged, and in a power cut switches the circuits wired to its backup ("essential loads") output to the battery, usually within about 20 milliseconds. That is often not the whole house: stoves, geysers and pool pumps are commonly left off the backup side because the backup output is limited. Hybrids are the usual choice for home solar and battery systems in South Africa.
Which one?
- You want lights and Wi-Fi in a power cut: a hybrid (or an inverter/charger) with a battery.
- You mainly want lower bills and the grid is reliable: grid-tie can be the cheapest.
- No grid connection: off-grid.
Whatever you choose, a registered electrician must do or supervise the wiring and issue a certificate of compliance (CoC). Any system that connects to the grid, even one that never exports, must use an inverter with an NRS 097-2-1 type-test certificate and be registered with your municipality or Eskom. Some, such as Cape Town and eThekwini, want you to apply before you install. See NRS 097-2-1 explained.
Written by the Halvora Directory team and checked against public sources (7 Nov 2026). General information, not advice for your installation.