The bigger machine is not simply a larger version of the smaller one. It is a different class of unit with different economics, and the cost per litre gap is bigger than most people expect.

Side by side

The number that decides most cases

The 80L draws 29% more power and produces four times the water. Run that through Johannesburg's top-block electricity rate and the gap is stark:

Roughly a third of the cost per litre. Over years of daily use that difference dwarfs the gap in purchase price — which is why anyone with real volume needs should look hard at the bigger unit even if the upfront number is less comfortable.

Four 20L units versus one 80L

For the same nominal output, one big machine wins on almost every measure.

The only genuine argument for multiple small units is distribution — a machine on each floor of an office, or one in a kitchen and one in a workshop, so nobody has to walk far. That is a real consideration, but it is about placement, not capacity.

Where the 20L is the right choice

• A household. Four people drinking 2 litres a day each is 8 litres — well within a 20L unit even at reduced winter output.
• A small office of under ten people.
• You want hot and chilled on demand from a self-contained unit. The 20L is built as a complete dispenser with a 12-litre purified tank, hot and cold tanks and push-cup dispensing.
• Space is tight. Its footprint is roughly 30 × 37 cm — about the size of a conventional water cooler. The 80L is nearly twice as wide and deep.
• Budget is the binding constraint. A lower entry price that does the job beats a better-value machine you cannot buy.

Where the 80L is the right choice

• Any office over ten people. The running cost difference compounds fast at volume.
• Guest houses, lodges, restaurants, clinics — anywhere serving numbers of people daily.
• You have somewhere for it to stand. It is a larger, heavier machine at 77 kg.
• You are feeding a storage tank rather than dispensing directly. It is designed to output to a tap or external tank.
• Cost per litre is your priority. Nothing else in the range comes close.
• You are in a drier region. Its 25% RH minimum and higher absolute output mean more usable water on marginal days.

The honest trade-off

The 80L is not simply better. It gives up things the 20L does well.

The 20L is a finished appliance: it collects, purifies, chills, heats and dispenses from a single stainless tank, ready to use where it stands. The 80L is closer to a water production machine — higher output, better economics, but it outputs to a tap or external tank rather than functioning as a complete self-contained dispenser with hot and chilled on tap.

For a kitchen where people want a cup of boiling water for tea, the 20L is the more directly useful object. For a site that needs volume, the 80L is not close.

Deciding

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