If you are a typical middle income family, 30-50% of your monthly electricity consumption is used heating water in your geyser/s. Clearly this makes electric geysers one of the main points of focus of any attempt to reduce your reliance on Eskom power and/or reduce your monthly electricity bill. To understand how an electric geyser uses electricity please see our water heating tests.
Energy Saving Tips
Install efficient nozzles to your shower, as well as your other hot water taps. These devices either inject bubbles of air into the stream or reduce the size of each drop of water leaving the nozzle. This makes the water feel as “substantial” as it would if there was no restriction. The result is that you use up to a 50% less hot water.
Install a heat pump. Heat pumps use far less electricity to heat water to the same temperature as a geyser would. One can reduce your water heating cost by up to 67%.
Install a geyser blanket. A geyser blanket is an additional layer of insulation which is wrapped around the geyser. You can reduce the frequency that the thermostat reheats water in the geyser substantially by doing this. Water in the geyser will stay hot longer during power cuts as well.
Insulate all water pipes leading to/from the geyser. Most pipes leading to/from from the geyser are normally left uninsulated. In most cases those pipes are copper. This creates an ideal path for heat loss from the geyser via both conduction and convection. To reduce this heat loss you should insulate all those pipes for at least 2-3 meters around the geyser.
Solar Water Heating: South Africa is blessed with one of the best climates in the world in which sunny days are by far the norm rather than the exception. Solar powered geysers make a lot of sense here! They reduce your total monthly energy consumption by about a third, depending on the type of geyser installed. This is a permanent saving as well as a permanent reduction of demand on the country’s electrical generation capacity. Many of the models available have electrical elements that will heat the water in the normal way during heavily overcast periods, so installing one doesn’t mean that the family has to put up with lukewarm water on rainy days.
Surviving a Power Failure
When the power goes off, water that’s been heated in the geyser obviously doesn’t instantly become cold. The geyser’s insulation is reasonably good at keeping the water hot for quite a long time (easily 4-8hrs). If the power goes off for only a few hours the water will thus stay warm enough for a bath or shower provided it had been heated fully before the power went down. The geyser’s function is affected more by longer power failures that last most of the day/night or more. However geysers are sensitive to when exactly in your daily cycle the power goes off. If the power fails just after the family has done their daily ablutions, when the geyser has just been emptied of all its hot water, then clearly it can’t heat the water until the power comes back up again. This may mean a cold shower if the power doesn’t come on early enough to allow the water to be heated.