Backup power for saunas and plunge chillers in South Africa

What the last decade left behind

Households here spent ten years buying inverters, batteries and rooftop solar. The grid has recovered — Eskom reports unplanned outages at their lowest in nine years and roughly R26.9 billion saved on diesel over three years — but the hardware is still on the wall.

That hardware is close to ideal for a wellness installation. A chiller is a small, steady load that a battery handles comfortably. A sauna heater is a large, brief load that is perfect for scheduling into the middle of a sunny day when your own generation is at its peak and grid electricity is at its most expensive.

The battery-backed chiller circuit

We put the plunge chiller on a backed circuit so the basin holds temperature through any interruption, planned or not. It is a small circuit — the compressor is not a geyser — and it means the one piece of equipment that suffers most from an outage never notices one.

For a club or a hotel this is not a comfort feature. A tub that drifts to twenty degrees and has to be pulled back down costs far more in electricity than keeping it cold did.

Scheduling the heater onto your own generation

A timer and a relay, wired so the cabin does its heat-up window when your panels are producing. On a household with a decent array this shifts the single largest load in the installation off the grid entirely for most of the year.

It is cheap to do at build time — a few thousand rand — and almost annoying to retrofit, which is why it goes in the first drawing.

What it costs

Indicative bands: 34 to 78 thousand rand for a battery-backed chiller circuit sized so the plunge holds through any outage, 12 to 26 thousand for heater scheduling on solar with a timer and relay, and 18 to 60 thousand for three-phase supply work where a large heater needs it. All of it is wired by a registered electrician and certified. Pair it with a cold plunge tub and the water never drifts.

In short

• Chiller on a battery-backed circuit so the plunge never drifts
• Heater scheduled into your solar window — the biggest load, off the grid
• A few thousand rand at build time, far more to retrofit
• Load shedding is over; the hardware it left behind is what we are using