Pouring cold water on energy myths

December 8, 2017, University of South Australia
Pouring cold water on energy myths

Fixated on those all-important energy ratings when buying a washing machine or dishwasher?

We've all been led to believe they are a credible guide to using our appliances more cost effectively but the reality may be a little different, according to new research findings from the University of South Australia.

UniSA PhD student Shiv Umapathi has been looking at the -energy footprint of eco-friendly households in Lochiel Park, a residential estate which prides itself on sustainable living.

The model green village uses three different water sources – rainwater tanks, and recycled water – and all homes are equipped with solar panels, resulting in an overall 64 per cent reduction of when compared with other households.

But Shiv's research has uncovered some useful findings relating to seasonal energy use among washing and dishwashers.

"Over the course of 12 months, I found that both appliances were more costly to run in winter. Regardless of their energy rating, washings machines used 31 % more energy in winter while dishwashers used 12% more. This was despite these appliances being operated fewer times in the winter months," Shiv says.

Pouring cold water on energy myths

"Some of the machines are energy efficient but not water efficient, and vice versa. What customers don't know is whether a washing machine or dishwasher is both energy and water efficient because those combined ratings are not available."

The other factor that people need to take into account is the temperature of the room in which the appliance is located. The machines are tested in ambient room temperatures (averaging 20 degrees Celsius) to gauge their energy ratings but these don't accurately reflect the temperature of laundries in most homes.

"In winter, it is likely that the laundry will be colder than 20 degrees Celsius in Adelaide and so the has to work that much harder to heat up the water to the required temperature. That makes it far more costly to run."

The energy use may also vary depending on other factors, such as the placement of pipes outside the house and which way they are facing, causing variations in water , Shiv found.

She advises consumers to choose appliances based on water (not ) ratings as 86 per cent of operational costs for washing machines and 58 per cent for dishwashers are attributed to water consumption.

Explore further: New efficiency standards for clothes washers, dishwashers

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4 comments

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aksdad
1 / 5 (1) Dec 09, 2017
So if I put two dishwashers in the same cold room, the one with the better energy rating will still use less energy than the other one even though it will use more energy than it would in a warmer room. Did I get that right?

So it sounds like we dumb consumers are right to be "fixated on those all-important energy ratings when buying a washing machine or dishwasher."

It sounds like those energy ratings are still "a credible guide to using our appliances more cost effectively." Thanks for pouring cold water on that "energy myth" that turned out to still be true. I feel better informed now.
rrwillsj
1 / 5 (1) Dec 09, 2017
ad, you are better informed now. Sounds to me that you understood this article, very well indeed.

Now we have gained more information than we had before. For those of us who are handymen, they could immediately perform incremental improvements to their homes. (Insulating pipes, heating the laundry room, etc.) Each adding a little bit to the building's over all energy efficiency.

And it ain't free. Many households would see substantial annual savings in what they spend for water and power. If they invested in adding electric-powered flash-water heaters at their busiest sinks. If you're remodeling a bathroom, do it for the shower.

And, now that you understand what the author of this article is telling you? You will be better prepared, shopping for new appliances.
SamB
5 / 5 (1) Dec 10, 2017
It would seem to me that my dishwasher would actually contribute to more energy savings in the winter than in the summer. In fact, you could say that the dishwasher would cost very little in the winter because all of the heat energy would be contributing to the heating requirements of the house. In the summer, this excess energy would cause my air conditioner to work harder, sending my power bills higher in the summer months.
rrwillsj
1 / 5 (2) Dec 10, 2017
SB, good points. What data do you have to support your contention? And, how would you accurately prove your contention is correct or incorrect?

And, if you prove yourself wrong? Would you admit that to yourself and make the effort to remedy your energy consumption?

Knowing, that at best, the investment with your labor and money, will only result in small differences in your utility bill?

As I said, there is always a price to be paid for everything we do and everything we fail to do.

Twenty years ago, forcing automobile manufactures to improve mileage standards, Is today, why you consume less gasoline per mile While your choices in cars have forced down the price of gasoline at the pump.

In addition to increasing motor efficiency. With cleaner fuels you spend less on maintenance. Removing lead from fuels has directly reduced the murder rate.

A lot of people still bitch & moan about not getting to drive an atomic-powered F1 on YOUR street. Cry me a river!

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