Does putting the geyser off save electricity? 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. By the same token, permanently keeping your geyser on won't save any more electricity either.
How does a geyser work? Your geyser is like a big kettle, (except your geyser is insulated). It has an element inside that heats the water up to a set temperature ideally 65deg.C
This temperature could be reduced if the geyser is close to the taps it is supplying, as the loss of heat while running through the pipes will be less.
You could have the hot water pipes from the geyser insulted (lagged) if the water has to travel a long distance before it gets to the taps, this should save some heat and reduce the amount of water wasted before the hot water gets to the tap you are at.
When a hot tap is opened, hot water is released from the geyser and cold water rushes back into the geyser to replace it; this is also what allows the pressure of the water out of the hot tap.
Because the cold water has been replacing the hot water in the geyser, the temperature in the geyser has now decreased, the thermostat registers that the temperature of the water has decreased and switches the element on to reheat the water back up to the set temperature of the thermostat.
Once the temperature of the water is back to the set temperature of the thermostat and no one is using hot water the temperature of the water in the geyser should remain the same, as no cold water is being let into the geyser. However, a small amount of heat will "leak" out of the geyser into the surrounding area and the rate of the heat leak depends on the quality of your geyser's insulation. These heat leaks will cause the water temperature inside the geyser to gradually decrease and the thermostat will periodically switch on to reheat the water when necessary.
The loss of heat is approximately 10% over a 24 hour period. It is important to make sure your geyser is well insulated, 99% of geysers are well insulated, a simple test, once your geyser is at the set temperature, touch it, it should be cold to the touch although the water inside is hot, (geyser blankets are a gimmick and are a waste of money), as mentioned above you could lag the water pipes, (this will save heat and electricity).
As for turning your geyser off when you are not at home this will not periodically switch on the geyser to reheat the water and therefore, you'll use less electricity.
But this doesn't take into account that once switched off, the water in the geyser eventually cools down completely and, when switched on again, a huge amount of energy is required to heat the water back up to the set temperature.
In most cases, more energy than if the element was periodically switching on throughout the day.
Installing a timer to switch off your geyser is just a lazy way of getting it switched off for you and as mentioned above will save you nothing.
The factors that affect the energy consumption of your geyser are: The condition of your geyser and the insulation, How much hot water you use and how often you use it.
So the best way to save electricity is as follows:- Only use hot tap when necessary – washing hands or face etc. can be done with cold water only, when you use hot water “use less” – shorter showers, shallower baths rather than long showers and deep baths; Switch the geyser off when going away for a few days – then it makes sense. Ensure your geyser and water pipes are properly insulated.
There you have it.
Using a simple calculation a 150L geyser uses a 3Kw element, this normally take approximately two and a half hours to get from cold to hot. Calculating at R2.50 per Kilowatt 3Kw X 2.5 hours = 7.5Kw 7.5Kw X R2.50 per Kw = R18.75 to heat up the geyser from cold to hot 65deg.C
Once on temperature and no hot water is used the geyser will switch on periodically for a possible total of 30 minutes per 24 hours to reheat 3Kw X 0.5 Hrs. = 1.5 Kw in 24 Hours 1.5Kw x R2.50 per Kw = R3.75 to reheat instead of R18.75
If hot water is used during the day it is obvious more electricity will be used, follow the guide lines above and all will be well.
ANOTHER REASON WHY IT IS NOT RECOMMENDED TO KEEP SWITCHING THE GEYSER OFF.
For those who have the basics of science from school and for those who have the HIGHER education prove me wrong if you can.
Scenario 1 The geyser element expands when heated much like the geyser itself and any other metals.
A metal that expand and contracts continuously gets weaker as time goes on and will eventually fail, once an element fails (cracks) it caused a fault and trips the power and inconvenience. You have to now call someone out to repair the problem and that costs you extra money you could have avoided.
Scenario 2 Because of the expansion and contraction of the geyser, the geyser bursts (cracks) water leaking all over, ceiling damaged, carpets, walls power tripping cupboards wet, and cloths damaged, you get the picture, not saying it will not happen under normal circumstances, but why promote it.
P.S. If you still insist on switching the geyser off, give us a call when the need arises.
HAVE A GOOD DAY AND KEEP SAFE and STAY WISE OUT THERE.
