Does Turning Down to 30 work?

Saturday 5th April, 2008
We've all read in the press and seen adverts on the TV about turning it down to thirty.

This refers to your washing machine and using programmes at lower temperatures. The days of the boil wash are pretty much gone and most people spend their time doing wash loads at 40 degrees Celcius. Modern detergents claim that they work just as well at 30 degrees and that by turning down to the lower temperature that the power saved would be enough to save the planet. If everybody in the UK turned down to thirty we'd save enough power to light all the homes in Belgium, or something like that.

But how true are these claims? Will turning down to 30 really save a significant amount of power, or will it just sell a load of compatible detergent?

Over the past few weeks we've been doing some electricity consumption tests here on Jaffa's Green Blog. This involves washing an identical load of towels, and drying them, in our resident Zanussi Jetstream Washer dryer. Obviously there's electricity used not just to heat the water, but also to turn the drum and drive the water pump

Initially we washed at the modern standard 40 degrees, which give us a benchmark figure for the power consumption. Washing and drying the towels consumed a total energy measurement of 2.67kWh. Obviously this figure would vary a little depending on how much laundry you had in the washtub. Larger loads may need less water, but would take more drying. This is why we only used the same towels in each test.

On week 2 we washed at 50 degrees, preferred by some as they claim it gets their clothes a little cleaner. Total power consumption was a surprising 2.76kWh...just 0.09kWh difference. Not as much difference as we expected and it didn't look good for when we did our 30 degree test.

So, week 3 is upon us and we did our usual washload. Standard measurements of detergent and fabric conditioner, along with our water softener tablet. A couple of hours later and the results were in..beep beep beep. Not quite sure why the Zanussi has to beep for quite so long but it is handy to remind you to go and take a meter reading.

30 degrees - 2.41kWh.

Yeah, I was surprised too. Whilst increasing by 10 degrees from 40 to 50 just used an extra 0.09kWh, we save a whole 0.26kWh by turning down to 30. It doesn't take a mathematical genius to work out that this was a 10 percent saving in power consumption. In real terms, that a saving of around 137 grammes of CO2 output. That's about the same emission as driving an average family car for a mile.

So for every wash load you do at 30 degrees, instead of 40, you offset the CO2 output of driving your 2.0 litre VW Golf for one mile. It's easier than planting trees!

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