With South Africa being an increasingly water-scarce and energy-costly country, we’re all keen to save more and waste less. So, what are the big users of water and energy? And what really works to reduce usage? Here’s the latest research and advice. Follow it, and you could slash your water and electricity bills.
Geysers are the biggest power guzzlers in our homes, accounting for 32% of a typical household’s energy consumption. But there has been conflicting advice on what to do about it. For instance, should you switch the geyser off at night? Or is the power required to heat its contents up from cold more than the little increments of power it uses to keep its contents warm if it’s on all day?
Fortunately, a research team at Stellenbosch University (SU) has taken the uncertainty out of the matter. They looked into various tried-and-tested methods of reducing your geyser’s electricity usage, including turning the geyser on and off, lowering the thermostat temperature, using a thermal blanket, or reducing your overall use of hot water.
“The best way to save on your household electric water heating is to start heating water two hours before and stopping before taking a shower or a bath,” says Professor Thinus Booysen of the SU Department of Electrical and Electronic Engineering.
The team of researchers compared eight typical household usages, from a one-person apartment with a shower to a four-person bathing household. The biggest saving from scheduling the geyser’s heating was from households with only one small usage event (a short shower) per day. Scheduling the heating of the water for that single use saved as much as 18% of a household’s power usage. For all the other usage patterns assessed, an average of 12% was saved, which is still a pretty good reduction.
Households with two baths per day, for instance, could save 10% on their household energy usage.
Fortunately, this significant cost-saving measure shouldn’t require any sacrifice. “An effective schedule will be able to deliver hot water on demand,” Thinus says.
Despite what you might have heard, turning your geyser on and off doesn’t damage your thermostat. You can do this manually or install a timer that costs around R300.
Insulating the pipes and the geyser can save between 5% and 12%. And doing this AND scheduling hot water usage will result in a total energy reduction of 25.1% for a single person home and 14.7% for a three-person household.
Turning the water temperature down from 65 degrees to 60 degrees results in similar savings.
While geyser science may deliver the greatest power saving from a single intervention, there are still many smaller steps you can take to reduce your power usage. Here are some tips from The Energy Office:
- Use CFL bulbs, solar lamps, motion detector lights or photocell/day-night lights for exterior lighting.
- Many appliances continue to draw a small amount of power even when they are switched off. These “phantom” loads occur in most appliances that use electricity. You can avoid this by unplugging the appliance at the wall.
- Instead of leaving appliances such as a TV or DVD player on stand-by mode, rather switch them off at the mains.
- A microwave oven is cheaper to operate than a stove.
- If you are about to buy or replace an oven, consider buying a convection oven, which uses less energy than a conventional oven and reduces cooking times substantially.
- It is cheaper to use an electric blanket in bed instead of a heater in your room.
- Install ceiling insulation fibre to keep your house warm.
In your home, depending on your appliances and usage patterns, the three biggest users of water are your bath or shower, your washing machine and your dishwasher. Here is how much they each use, on average, according to the Cape Town Green Map:
- An average shower uses 20 litres of water per minute – so a five-minute shower will consume 100 litres of water.
- Regular dishwashers use on average of 40 to 75 litres per wash. Very efficient dishwashers can use as few as 13 litres.
- Washing machines on average use 150 litres per wash. High-efficiency machines use about 30% less – so you’d be using just over 100 litres per wash. And you can find some machines that use as little as 40 litres per wash on the correct setting.
Even if you’re really committed to water saving, you’re unlikely to dash out and buy more efficient dishwashers and washing machines solely for this purpose. But consider the savings the next time you are buying a new machine. You can also make sure that you always run your appliance on the most energy- and water-efficient setting - low heat and short cycle. Wash less frequently, and always wait until you have a full load.
That leaves showering as the water-using activity that you have the most control over. You can shower for less time (as most of Cape Town has learnt in the last year), but you can also install a high-quality energy- and water-saving showerhead for around R240 that will cut your water usage in half. Such a shower head can cut water usage to just nine litres per minute, so a five-minute shower would use only 45 litres of water, instead of the 100 litres of an average showerhead.
Again, the best water savings will be achieved by taking all the steps you can to reduce your usage. Try these recommendations from the Worldwide Fund for Nature, South Africa:
- Turn off the tap while brushing your teeth and save nine litres.
- Use a pool cover to reduce evaporation.
- Fix leaky taps – even a slow drip can waste 30 litres a day.
- Wash your car infrequently and use a bucket rather than a hose.
- Put buckets in the shower for runoff water and under downpipes to catch water during rain for your garden.
- Plant a water-wise garden with indigenous drought-resistant plants.
- Water your garden after 6pm.
- Use a watering can to make sure the water goes where it’s needed.
Save water, save electricity, save money
There are loads of good reasons to save water and electricity, but the one that probably has the most direct impact on you is that it saves you money. By reducing the power consumed by the single biggest energy user in your home, your geyser, you could knock 10% to 20% off your electricity bill, and by installing a water-efficient showerhead, you could save 50% of the water you use every time you shower. These are real savings, and worth considering seriously.
the three biggest users of water are your bath or shower, your washing machine and your dishwasher