What temperature to set the geyser thermostat, and why lower is better

The dial on the geyser is usually left wherever it came from the box, which is often near maximum. That costs money and shortens the geyser's life, and it is a scald risk.

The sensible setting

Around 50 to 55 degrees for most homes. Hot enough for a comfortable shower with a little cold mixed in; not hot enough to scald in the second it takes to pull a hand back.

Why not hotter

• Scale forms faster above 60 degrees — in hard water, much faster
• Standing heat loss rises with temperature, so a hotter tank wastes more between uses
• Scald risk: water above 60 degrees burns skin in seconds
• The element and thermostat cycle more, and wear faster

Why not colder

Below about 45 degrees a storage tank can support bacterial growth. Keep it at 50 or above and that is not a concern.

Finding the dial

On most storage geysers it is under a small cover on the front or bottom, marked with a range or with min/max. On some it is inside the casing and needs a technician. Instant geysers usually have a front knob.

Switch the geyser off at the MCB before removing any cover to reach the thermostat. If the dial is behind the main casing, do not open it — that is a visit.

A good habit

Set it once, at about 55. If you find yourself running the shower on pure hot with no cold mixed in, the geyser is not the problem — the tank is undersized or the element is scaled.