Monday, 12 February 2007

Dishwashers vs Washing Up By Hand

I finally found some source research on whether it's more economical to run a dishwasher or to do the washing up by hand. Several people have told me scientific trials have shown that a machine uses less water and less energy than washing dishes by hand, but it seems so unlikely that I've never quite believed it.
You can read some "scientific" research for yourself here: http://www.landtechnik.uni-bonn.de/ifl_research/ht_1/EEDAL_03_ManualDishwashing.pdf
Suffice to say, I was right all along.
The trial participants who did the washing up by hand weren't even TRYING to save water or energy. Some of them, as I had suspected, just let the hot tap run the whole time - some even when they were DRYING the dishes!
The water and energy used to manufacture, transport and dispose of the machine at either end of its useful life were not accounted for, and neither was the energy wasted by the damned things when they finish washing but don't turn themselves off. Another appliance on "standby", another huge waste of energy.
There's no mention either of the environmental damage caused by very nasty chemicals found in dishwasher detergent, which are much worse than normal washing up liquid.
They do, however, factor in the effects of running the machine half-empty sometimes. It's just a pity they didn't deal with the average washer-up's half-empty head...

6 comments:

commoner said...

I firmly believe that the most eco-friendly way to wash dishes is to let them accumulate for a week or two, or at least until there the kitchen surface space is completely covered to a depth when plates tend to slide off when placed on top of the heap. This procedure should be combined with eating one-pot recipes straight from the pan. The result is that you only have to do a single washing-up every month or so, thus significantly reducing water wastage and detergent use at a stroke!

For some strange reason none of the women I have lived with have ever supported this way of protecting the environment. Nor have they realised that male DNA lacks a crucial gene that means that they cannot recognise the phrase "It's time to do the washing up" (however loudly shouted), while there are at least 100 genes that respond to the phrase "It's time for sex" (even when whispered several floors away). Ho hum...

Alice said...

I have made lots of interesting art by leaving dirty mugs for a long time. I grew beautiful blue mould on the surface of some old coffee, for instance, which you could see reflected around the inside of the mug like a kaleidescope.

I don't think those genes are only found in men.

commoner said...

I can do great stuff with beetroot (http://www.sfu.ca/%7Elogilvy/july/july-17.html)!!

Alice said...

That's beautiful. I'm just planting beetroot...

Anonymous said...

for the record...
I've just washed by hand what would normally fit in my dishwasher. I used 6L hot water and 4L of cold water, and 3ml of detergent 2.5kWhr to heat water. Only electricity was heating 6L of water. A brand new dishwasher uses 13.6L of water and 267kWh electricity. - so you do save water and electricity by hand washing.

Anonymous said...

Labour and effort needed to put dishes into a dishwasher, and then get them out again, deters me. Why bother when they can go from surfsce to sink to cupboard?