Dishwasher vs Handwashing: the Winner
We have been asked if washing by hand or with a dishwasher is more efficient. This article by Treehugger.com helps shed some light on the issue at hand...
August 13, 2005 03:57 PM - Christine Lepisto, Berlin
We recently covered a tip on dishwasher efficiency, but may have left you still feeling guilty or at least wondering about whether you should be pampering yourself with this labor-saving appliance. Now, thanks to a scientific study at the University of Bonn in Germany, you can have your cake and eat it too-relaxed in the knowledge that the cleaning up with your trusted machine will be a piece of cake and the eco-friendly thing to do...
The Bonn study proves that the dishwasher uses only half the energy and one-sixth of the water, less soap too. Even the most sparing and careful washers could not beat the modern dishwasher. The study also rated the cleanliness achieved, again in favor of the washing machine (sorry grandma). There have been studies before, but this is one of the few that stands (wo)man against machine and it sets itself apart by including a thorough analysis of the effect of half-loads and the whole demand range from your cake plate to the grimiest pots. Surf to research under household technology at U. Bonn's site for more. :: U. Bonn Household Technology
CO2 emissions of dishwashers
On 5/16/06 9:59 AM, someone wrote in with this question on the above:
Hi,
I read an article somewhere- wish now I could remember where- that dishwashers emitted a lot of CO2, which ultimately made them the loser. Have you read anything about this?
Dishwasher-curious.
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Hi Dishwasher-curious,
Any CO2 emitted because of a dishwasher would only be in direct proportion to the energy used to heat the water and run the washer. In a typical residential building, the energy used to heat the water would be the same whether the dish was washed in a dishwasher or in your sink: the water would most likely be heated by a gas or oil boiler in your basement. A dishwasher, however, would also use electricity, which has a different CO2 make-up depending on how the electricity was generated. However, for much of BC which is hydro powered, electricity has a very low CO2 make-up.
The German study, like a lot of others that have assessed handwashing v.s. Dishwashing, looked at the sum of all the energy for both options, and overall found that dishwashing used significantly less energy. I guess the only time where it might make sense to wash dishes by hand for environmental purposed would be if your method of heating water was much more benign (for example, if it used waste heat and therefore had no assciated CO2 or if it was heated through solar panels which also have no CO2 associated) AND your electrical source (unlike ours in BC) did have a high CO2 emission associated with it (coal or gas etc.) Otherwise, this German study is a good guide for us in BC.
Jessica
I think it depends on the
I think it depends on the dishwasher and person washing the dishes, if the dishwasher can reuse water rather then constantly flowing/emptying fresh water it may take up more, where with hand washing you can fill up the sink with water and soap and go through a lot of dishes before having to change the water. Our dishwasher is over 10 years old and broke a few times we found some appliance parts online for it but figured it would be much better to buy a new energy efficient one that can even use steam to clean the dishes which uses a whole lot less water.