Tips to save electricity this winter
We all rely on geysers for hot water – but have you ever stopped to think about how they work, and whether your one is as energy efficient as possible?
Take for example the average household with
a 150-litre geyser, consuming about 200 litres of water per day. If this geyser
is switched off for 15 hours a day and set to a temperature of 60°C you will be
able to save up to 122kWh and R67, compared to a geyser set at 70°C, and left
on all day.
Even reducing the geyser’s thermostat temperature from 70°C to 60°C, without turning the geyser off during the day, will achieve a small saving. However turning it off manually can be quite problematic if you lead a busy life, and want to rush home for a quick shower between work or gym and a social event for example.
One solution is to install a geyser timer, so that your geyser comes on before hot water is required, for example for a few necessary hours in the morning and again in the evening. The great thing about timers is that they can be perfectly adjusted to suit your individual needs.
As with most things in life there are two schools of thought around this though. Not everyone agrees that turning your geyser off during the day and turning it up again in the evening saves electricity... as by switching the geyser off, the water inside will eventually lose heat, so when you turn it on again, it will have to heat the water from a much lower temperature than before. This may make you consume more energy that you would have by simply keeping it at a consistent temperature.
Another option to consider is a heat exchanger. This is an interface within a geyser, or attached to an external setup, that allows efficient heat transfer between two mediums. A heat pump is the plant that can pump heat into a medium by extracting the heat out of another. You can connect a solar setup, heat pump or other systems like geothermal all to their own heat exchanger. A heat pump is almost like air-conditioning in reverse and plays with compression, whether you want to cool or heat.
There is no general one-size-fits-all type solution to the issue, especially as there are many different technologies, which lead to different results. That said, the most important things to keep in mind to save up energy are:
- Try to use less water - shower rather than bath, for shorter periods and avoid hot water for anything other than showering (such as washing hands).
- Turn the geyser off only if you’ll be away for longer than 24 hours.
- Ensure you have proper insulation for the geyser and pipes.
- If you still have an old geyser, opt for an upgrade or, even better, a solar water heater.
- Use a heat exchanger.
The main problem in South Africa is that the demand for energy outstrips the supply, especially in winter and during peak hours. Solar water heaters represent a viable solution to the problem.
Essentially to install a solar geyser, all you'll be doing is circulating solar-heated water through a continuous loop of plumbing that runs from the roof mounted panels down to a heat exchanger, through a pump, and back to the panels again. The heat exchanger is simply a tank-within-a-tank that transfers the approximately 60°C warmth of the loop water to the considerably cooler supply reservoir surrounding it.
Fittings tapped into that reservoir allow it to be placed in line between the city water source that feeds your house and the cold water inlet pipe to your electric or gas hot water heater.
Of course, for any installation to work, your site must be suitable for a solar application. Whether you plan on having a roof or a wall-mounted system, make sure that no obstructions — especially buildings or trees — will be in front of the collector panels. Remember that you'll be using hot water the whole year round, so in addition to sighting the morning-to-evening swing of the sun, check the solar altitude at the winter and summer solstices.