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Galvio Enterprises

Buying guide

Which Geyser Size Do I Need? A Water Heater Guide for Winter

Quick answer: For one bathroom used by 1–2 people, a 10–15 litre storage geyser is enough. A family of 3–4 that bathes by bucket is better served by 25 litres, and 35–50 litres suits larger families, back-to-back baths or a bathtub. For a kitchen sink or wash basin, a 3 litre instant water heater is quicker and cheaper.

Size by use

A storage geyser heats a tank and keeps it hot; how many people bathe one after another matters more than the size of the bathroom. An instant water heater heats a small amount quickly and suits short, frequent use.

UseSuggested sizeType
Kitchen sink or wash basin1–6 LInstant
1–2 people, one bathroom10–15 LStorage
Family of 3–4, bucket baths25 LStorage
5+ people, back-to-back baths or a bathtub35–50 LStorage

What else to check

  • Star rating: on a storage geyser, more BEE stars means the tank loses less heat while it waits, so it switches on less often
  • Pressure rating: flats on high floors or with a pressure pump need a tank rated for higher pressure (8 bar is common)
  • Hard water: a glass-lined or enamel-coated tank and a magnesium anode last longer where water leaves white deposits
  • Safety: a thermostat, a thermal cut-out and a pressure-release valve, with the geyser on its own earthed socket
  • Space: a horizontal or square model fits a bathroom with a low ceiling or over a door

Buying before winter

Demand for geysers, and for plumbers to fit them, rises sharply once the cold sets in. Buying and fitting a few weeks earlier means a wider choice of sizes and an installation date that suits you.

See all water heaters

Storage geysers for a family bathroom (15–25 L)

Frequently asked questions

It can be if people bathe at different times, since the tank reheats in between. If everyone bathes one after another in the morning, a 25 litre geyser avoids the last person getting cold water.

Updated October 2026. Written by Galvio Enterprises. Prices shown are our current selling prices.