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    What Size Geyser Do I Need? A Household Sizing Guide

    Choosing between a 100L, 150L or 200L geyser for your Johannesburg home — how household size, bathrooms and habits decide it, and the cost of getting it wrong.

    14 June 2026 6 min read
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    Running out of hot water halfway through a shower is one of the most common complaints we hear — and it almost always comes down to a geyser that was sized to the price tag rather than the household. Here is how to get it right.

    The quick sizing guide

    • 100L — 1 to 2 people, one bathroom.
    • 150L — a family of 3 to 4. The most common household size.
    • 200L — 4 to 6 people, or two bathrooms used around the same time.

    If your household showers back-to-back in the morning, or you have a big bath, size up a notch.

    Why bigger is not automatically better

    An oversized geyser keeps more water hot than you ever use, and pays to reheat it around the clock. The sweet spot is big enough that you do not run out, small enough that you are not heating water you never touch. A GeyserWise controller helps either way by heating to your routine instead of 24/7.

    What replacement costs

    A supplied-and-installed 150L electric geyser starts from around R5,500 including the Certificate of Compliance; 200L and high-pressure units cost more. If running cost matters more than upfront price, look at a solar geyser or heat pump on our hot water systems page.

    Can you go bigger than you have?

    Usually yes — but a larger geyser is heavier and draws more, so the bracket, roof space and circuit must suit it. We check all of that on site and quote any changes upfront. See geyser installation or ask us to size yours.

    Frequently Asked Questions

    As a rough guide: 100L suits 1–2 people, 150L suits a family of 3–4, and 200L suits 4–6 people or homes with two bathrooms used at similar times. Households that shower back-to-back or have a large bath should size up, because running out of hot water mid-shower is the most common sizing complaint.

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