It comes down to how many hot taps run at the same time, whether you have power at the unit, and what your water pressure is doing. A 20L unit is the right call for a family home with two bathrooms; a 16L is plenty for a flat or a granny flat. Below is what we actually install, with honest pricing.

Paloma 20L
Whole-house premiumFrom R22,000 supplied & installed
The unit we fit when a household runs two bathrooms and a kitchen at once. Excellent temperature stability and build quality. Needs a plug point — it runs off electricity, not batteries.
See the Paloma 20L →
Rinnai 20L
Premium whole-houseFrom R21,500 supplied & installed
The same premium whole-house performance as the Paloma, manufactured in Japan, and R500 apart on the installed price. Also mains-powered, so it needs electricity at the unit.
See the Rinnai 20L →
Dewhot 16L Constant Temperature
Mid-market family homesFrom R15,000 supplied & installed
Constant temperature control at a sensible price, and it is battery-powered, so it keeps making hot water through load shedding. A solid choice for a three-bedroom house with one main bathroom.
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Cadac 16L Ecoflow
Flats, granny flats, low pressureFrom R12,200 supplied & installed
The entry-level workhorse. It lights on low water pressure, which suits flats and older Pacaltsdorp plumbing, and runs on batteries. Best for one bathroom at a time.
See the Cadac 16L Ecoflow →Cadac 12L Ecoflow
Granny flats, small unitsFrom R11,000 supplied & installed
Suitable for a granny flat. Battery-powered with a low-flow start, sized for one shower or a kitchen at a time. Cylinders, cage, cover and a flue where required are quoted as extras.
See the Cadac 12L Ecoflow →Sizing is not only about litres per minute. The length of your pipe runs, where the cylinder can safely stand, and how many showers run at once all change the answer — which is why we look at the house before quoting. Our gas geyser buying guide walks through the trade-offs in more detail.