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New washing machine (at least in the EU) often have a special program named with something like "green" or "eco" and that are supposed to be environmentally friendly. These are often for around 2–4 hours, compared to the other programs (on the same machine) which are for around 45 minutes to an hour and a half.

My question is, how do these programs differ from each other and what makes the "green" programs more environmentally friendly? I know different machines won't have the exact same programs, but in general:

  1. Do they use lower energy?
  2. Do they use less water?
  3. Is there more or less wear on the textiles?
  4. Any other differences?
Sklivvz
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citizen
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    The key point is that they use cold water at pipe temperature and do not heat it. – Henry Sep 15 '12 at 00:38
  • I have that on my dishwasher. On the other hand the eco program on my washing machine is much shorter than the normal program so one can probably not always generalise. – nico Sep 15 '12 at 06:51
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    [Welcome to Skeptics](http://meta.skeptics.stackexchange.com/q/1505)! We want to focus our attention on doubtful claims that are widely held or are made by notable people. Can you [provide some examples](http://meta.skeptics.stackexchange.com/questions/882/what-are-the-attributes-of-a-good-question/883#883) to places where this claim is being made? – Sklivvz Sep 15 '12 at 09:11
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    By far the most significant energy consumption of washing machines is heating the water. The power used driving the drum is very small by comparison. So essentially the time taken to wash the clothes is irrelevant to the power consumption. If washing for a longer time allows it to be done in cold water, then these programs might well consume less energy. However there is no way of giving a definite answer to this without knowing the details of each program. – DJClayworth Sep 15 '12 at 15:40

1 Answers1

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The energy saving is in not heating the water.

From the web-site of a random manufacturer:

How does it all work?

Your washing machine uses the most energy when it's heating up the water at the beginning of the wash cycle. So Hotpoint's Eco Cycles simply don't heat up the water - that's how you can achieve fantastic energy savings of between 50% - 70% *.

*Compared to an equivalent 30°C cycle, as verified by internal testing.

They go on to explain they don't consume more water:

enter image description here

Oddthinking
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    Worth noting: There are downsides to washing in cold water. [Dust mites.](http://www.webmd.com/allergies/news/20070521/hot-water-removes-allergens-best) (I heard an expert once joke that washing your clothes in cold water just means your clothes are covered in clean dust mites.) – Oddthinking Sep 17 '12 at 01:35
  • Washing with 30°C will also just give you clean mites, as far as I know. To get rid of mites, deep freezing is supposed to be more effective than washing `:-)` – Hendrik Vogt Sep 17 '12 at 13:36
  • @Hendrik: My link agrees that 30°C isn't hot enough and recommends 60°C (or else repeated long, cold rinses). – Oddthinking Sep 17 '12 at 14:10
  • Thanks for the confirmation! (Sorry, I failed to follow your link ...) – Hendrik Vogt Sep 17 '12 at 17:17
  • another thing worth noting is that dirt will build up in the drum when washing with cold water (and start stinking up the machine), you need to do a high temp wash once in a while (once a week or so) to flush it out properly (personal experience) – ratchet freak Sep 17 '12 at 20:51