7 myths debunked about switching off your geyser

Homeowners across South Africa have been encouraged to switch off their geysers to save electricity, but does this make any difference to the overall demand? Get the facts…

When you have thousands of geysers all running during the day and night, this places tremendous strain on the supply grid.

Craig Berman from Saving Energy debunks some common myths…. 

1. Switching off the geyser doesn’t have a substantial impact on overall electricity demand 

Craig says in an average household, the geyser accounts for around 40% to 60% of the total electricity used in a month. 

So when you have thousands of geysers all running during the day and night, this places tremendous strain on the supply grid. 

Craig says this is the primary reason that Eskom frequently requests consumers to install geyser timers that control the geyser’s operating times. He says this also ensures that the geyser is off during peak demand periods. 

The Eskom Residential Mass Rollout (RMR) programme specifically targeted household geysers and recommended the installation of both geyser timers and geyser blankets to reduce demand. 

Using a timer on your geyser is a more efficient way of managing electricity demand.

2. Switching the geyser on and off consumes more energy 

According to Craig, a geyser operates by using electricity to heat water to the set temperature of the thermostat. 

He says once the heat from the water dissipates due to natural thermodynamics, the thermostat then switches the element back on to reheat the water. This cycle can happen 15 to 30 times per day. 

Most people don’t need hot water throughout the day and so a lot of electricity is wasted when the geyser is heating water when not required in the home. 

A 150 litre geyser needs about an hour to heat water to the set temperature from cold. So switching the geyser off when hot water is not required and switching it on an hour or so before hot water is needed will cut the amount of electricity used. 

Alternatively, the geyser will simply run for 24 hours, resulting in high electricity wastage, especially in winter, and more so if the geyser does not have a geyser blanket to prevent the additional heat loss, he says. 

3. Switching a geyser on and off damages the thermostat 

A family of four that needs hot water in the morning and evening for showering or bathing, and only some during the day for dishes etcetera, doesn’t need to have their geyser running 24/7.

Absolutely not, says Craig. The thermostat switches on and off during the normal operational cycle anyway. 

He says the only damage will occur to the geyser breaker switch as it is designed to trip only when there is a problem with the geyser. He says it is not designed to be frequently switched on and off. 

4. Switching a geyser on and off will cause it to crack 

No, definitely not. Craig says the geyser switches on and off during normal operation and is designed to withstand the temperature and pressure created as the water heats up. 

5. If you use a geyser blanket, the geyser doesn’t need to be switched off 

No. According to Craig, while the blanket assists with reducing heat loss, keeping the water hotter for longer, which in turn results in less electricity being used - when the geyser does switch on, the average saving achieved with a geyser blanket alone is only about 8%. 

He says controlling the operational times of the geyser using a timer would add between 15% and 18% savings over and above the blanket. 

Energy- and water-saving showerheads reduce the flow volume of the water by more than half.

Controlling the geyser’s consumption offers greater energy saving than just the blanket, he says. In short, a geyser timer alone is about twice as effective in reducing energy usage than using a geyser blanket alone. 

6. Geyser blankets can overheat, explode or catch fire 

No. Craig says geyser blankets that are made from recycled PET (2L Coke bottles) don’t burn, overheat or explode. He says if there was a fire in the roof, the blanket would simply melt in the heat. 

7. Using a timer on your geyser is a more efficient way of managing electricity demand 

Most definitely. As a company that has installed more than 1 000 geyser timers, Craig says they know that switching the geyser off during peak demand, and operating based on the water usage patterns of the household, makes a significant difference in both cost and demand to both the consumer and the grid. 

How can homeowners use their geysers more efficiently? 

Install a geyser timer, geyser blanket and energy- or water-saving showerheads: 

-  Know your water usage patterns and then have a timer or similar controller installed to ensure that your geyser only operates to meet those usage requirements. 

For example, a family of four that needs hot water in the morning and evening for showering or bathing, and only some during the day for dishes etcetera, doesn’t need to have their geyser running 24/7. 

With a timer and blanket installed, having the geyser come on at around 4am and off at 6am will provide enough hot water for the morning up to around 12 midday, without having to run the geyser again. 

You can have the geyser on between 1pm and 2pm just to maintain the water temperature. From there, the geyser can be switched off until around 4pm, and can then stay on until 6pm. Thereafter, switch it off for the rest of the night. 

This way, the geyser is not running during peak demand periods and contributes to lower demand on the grid, while efficiently supplying the hot water needs of the household. 

-  Energy- and water-saving showerheads reduce the flow volume of the water by more than half. An average showerhead can use around 20 litres of water per minute, of which around 40% is hot water. 

In a single 5-minute shower, that amounts to 100 litres of water and 40 litres of that is hot water. 

Four people having a 5-minute shower twice a day would use 800 litres of water and 320 litres of hot water. 

Installing energy and water efficient showerheads will reduce that flow to just 9 litres per minute.