Does switching off the geyser really save energy?


Your geyser is essentially a giant kettle. Imagine keeping your kitchen kettle running all day so that you constantly have boiling water for your tea and coffee. Seems like a lot more electricity use, right? There have been many debates about whether keeping your geyser on permanently costs more electricity than if you only turned it on when you needed it. We’re here to set the matter straight once and for all, so that you can optimise your electricity use and environmental impact.

The main argument for switching off your geyser is that when off, the element in the geyser is not heating the water and therefore not using electricity. However, if a geyser is kept on, the water is permanently at high temperatures, requiring little or no heating from the element. The element will only be using higher amounts of electricity after the hot water has been used and new, cold water refills the geyser chamber. When the geyser is switched off, the water inside the geyser will grow cold, and to heat the entire volume of water will require more energy (electricity).

2 Sides to the geyser story

The two sides of the argument seem to cancel out; leave a geyser to get cold and a massive amount of power is required to turn it back on, or use less electricity but over a longer period of time to keep your geyser temperature constant. Energy is being used either way you do it. In fact, geysers account for up to 40% of your household electricity bill. Reducing your geysers energy consumption is ideal, not only for your monthly expenses but also for the environment.

To understand whether leaving a geyser on or switching it off periodically is more energy efficient, a thorough investigation is required. Some geyser makes are designed to heat up faster, which requires a lot more energy, but will maintain high temperatures without much energy use. Modern geysers are already manufactured to be more energy efficient than older models. Other factors also come into play that will determine whether your geyser is using more electricity than usual.

4 Factors affecting energy use

Factors affecting energy use in your geyser:

  • The type and condition of your geyser
  • How much hot water you use
  • How often you use it
  • Insulation

According to most professionals, including Eskom’s Geyser Fact Sheet, turning off your geyser will not save much electricity. For 24 hours after your geyser is switched off, only 10°C of the heat is lost. This is called a ‘standing loss’ and is a quality standard set by the SABS. Using this slightly cooler water instead of reheating it may save a small amount of electricity, but when the geyser is turned back on, the electricity needed to reheat the now diminished temperature will cancel out those savings.

By the same token, permanently keeping your geyser on won’t save any more electricity either. You can, however, save on electricity by switching your geyser off if you don’t plan on using it for an extended period of time, for example when away on holiday.

6 Ways to save electricity

How can I save electricity with my geyser then?

Use insulation
Insulating your geyser with a thermal blanket, as well as insulating the pipes, will prevent heat from escaping the geyser and thus using more energy to compensate for this loss. Keeping your geyser running with proper insulation will reduce the amount of energy required to maintain high temperatures. Tests have shown that effective insulation saves about 20% of electricity when reheating a geyser that has been off for 24 hours.

Correct thermostat settings
Set your geyser’s thermostat to 60°C to optimise your electricity use. Higher temperatures are unnecessary and will use more energy.

Install your geyser as close to the areas where hot water is needed as possible
This will reduce the cooling down of water resting in the pipes.

Use cold water instead
When washing your hands, clothing or dishes, hot water is not always necessary. Lower the temperature settings on your washing machine and dishwasher.

Install a water- and energy-saving showerhead
This can save up to 24% in electricity and water use.

Solar power
It may be costly to install, but a solar water heater will save vast amounts of energy and is more environmentally friendly.

You can save electricity by managing your hot water use, and taking care of your geyser. Older or damaged geysers will drain electricity. Whether you turn off your geyser regularly or keep it running, your savings will only be affected by responsible management.


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