Comments on: Running the numbers on dishwashing http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/ Learning to live green and live together Fri, 25 Jul 2008 01:09:19 +0000 http://wordpress.org/?v=2.5.1 By: Green House » takes guilt out of your way http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-397 Green House » takes guilt out of your way Sun, 27 Apr 2008 03:14:58 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-397 [...] I see that local green bloggers Will & Maggie have also had dishwashers on the brain, and their own experiment was less favorable to the [...] [...] I see that local green bloggers Will & Maggie have also had dishwashers on the brain, and their own experiment was less favorable to the [...]

]]> By: Will http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-345 Will Fri, 18 Apr 2008 03:06:06 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-345 Yeah, I found the Bonn study in my research and couldn't get it to make sense, so I calculated it myself (and I'm glad I did, since my results are so different!). Their dishwasher number comes out to 4 gallons per load for normal use, which is about half what it is here, so that does make a difference. Even so, that would have been less than the most frugal of their human washers, so I'm not sure what's going on there. It's possible that the test kitchen was set up in a way that encouraged water use or that people were less careful when washing dishes they weren't going to use. Another possibility is that the dishes used (place settings) were compact and thus favor dishwasher use. I suppose the average person might use 14 times as much water as I did, but that seems hard to believe too. I guess my next test should be to fill the dishwasher and then wash all of <em>those</em> dishes by hand and see how that comes out. Until then, I'll continue to wash compact items in the dishwasher and pots/pans by hand. Yeah, I found the Bonn study in my research and couldn’t get it to make sense, so I calculated it myself (and I’m glad I did, since my results are so different!). Their dishwasher number comes out to 4 gallons per load for normal use, which is about half what it is here, so that does make a difference. Even so, that would have been less than the most frugal of their human washers, so I’m not sure what’s going on there.

It’s possible that the test kitchen was set up in a way that encouraged water use or that people were less careful when washing dishes they weren’t going to use. Another possibility is that the dishes used (place settings) were compact and thus favor dishwasher use. I suppose the average person might use 14 times as much water as I did, but that seems hard to believe too.

I guess my next test should be to fill the dishwasher and then wash all of those dishes by hand and see how that comes out.

Until then, I’ll continue to wash compact items in the dishwasher and pots/pans by hand.

]]> By: Dana http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-343 Dana Thu, 17 Apr 2008 19:52:57 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-343 Via Plans, I found <a href="http://environment.about.com/od/greenlivingdesign/a/dishwashers.htm" rel="nofollow">this link</a> that references a study done by scientists at the University of Bonn that claims dishwashers are more efficient that the average hand dish washing person. It, in turn, links the actual PDF of the study. Of course, things to keep in mind include that this was 1) done in Europe, where perhaps appliances run on different efficiency standards, and 2) they're talking about <i>average</i> people. Via Plans, I found this link that references a study done by scientists at the University of Bonn that claims dishwashers are more efficient that the average hand dish washing person. It, in turn, links the actual PDF of the study.

Of course, things to keep in mind include that this was 1) done in Europe, where perhaps appliances run on different efficiency standards, and 2) they’re talking about average people.

]]> By: Will http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-339 Will Thu, 17 Apr 2008 15:01:04 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-339 SDG: Thanks! I think home experimenting is a really important part of going green. What works well for other people might not work well for you at all! arduous: We probably should wash sooner, but we have trouble keeping a good flow going. We always seem to have stuff drying in the drying rack when it's time to wash dishes. When that happens, I put a little cold water into my pots and pans which I dump into the warm water when I do finally wash. equa yona: Urban Mom's prewashing numbers are interesting, but we pre-rise just to keep food from smelling before we run the cycle. When I experimented with not pre-rinsing, we were still able to clean everything with the short cycle. Andy: Wow! That's not much water at all! SDG: Thanks! I think home experimenting is a really important part of going green. What works well for other people might not work well for you at all!

arduous: We probably should wash sooner, but we have trouble keeping a good flow going. We always seem to have stuff drying in the drying rack when it’s time to wash dishes. When that happens, I put a little cold water into my pots and pans which I dump into the warm water when I do finally wash.

equa yona: Urban Mom’s prewashing numbers are interesting, but we pre-rise just to keep food from smelling before we run the cycle. When I experimented with not pre-rinsing, we were still able to clean everything with the short cycle.

Andy: Wow! That’s not much water at all!

]]> By: Andy http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-331 Andy Wed, 16 Apr 2008 21:38:24 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-331 I think you have a good experiment here. I have often heard that it's roughly he same impact whether by hand or by machine, but I disagree. I wash everything by hand and I would say that I average about half a gallon of water for the equivalent of a full load in a dishwasher. Half gallon?! I know it sounds like nothing but hear me out: I put about an ounce of water on the first thing I wash, as well as some soap. I then rub everything down using that water and my hands. The water is then poured onto the next item. So far I've only used an ounce. Then, if food is still sticking I use a sponge and scrape it off, with no additional water usage. I then rinse everything in running water which accounts for almost all the water usage. So half gallon and only electricity to heat and pump that half gallon is certainly more sustainable then running a load in a dishwasher. -Andy I think you have a good experiment here. I have often heard that it’s roughly he same impact whether by hand or by machine, but I disagree. I wash everything by hand and I would say that I average about half a gallon of water for the equivalent of a full load in a dishwasher. Half gallon?! I know it sounds like nothing but hear me out: I put about an ounce of water on the first thing I wash, as well as some soap. I then rub everything down using that water and my hands. The water is then poured onto the next item. So far I’ve only used an ounce. Then, if food is still sticking I use a sponge and scrape it off, with no additional water usage. I then rinse everything in running water which accounts for almost all the water usage. So half gallon and only electricity to heat and pump that half gallon is certainly more sustainable then running a load in a dishwasher.
-Andy

]]> By: equa yona http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-329 equa yona Wed, 16 Apr 2008 17:54:49 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-329 Hmmm, Going Green wrote about dishwashers today, check her numbers if you haven't already <a href="http://burbanmom.blogspot.com/2008/04/207-powder-to-people.html" rel="nofollow">http://burbanmom.blogspot.com</a> I do it a bit differently in that I start with an inch or two of soapy water and rinse over my dishpan. I save all my dishwater to flush the toilet and my hot water heater is set at tepid(or thereabouts). I usually toss the bottom cup or two of really scuzzy water although why i don't just flush it all is beyond me. It can't be too scuzzy for the crapper can it? Ok, no electricity used, about three gallons of water warmed w/ natural gas, no water wasted. Our counters are low as well and I am 6'3". [Edited by Will to add a link to Urban Mom's post about dishwashing] Hmmm, Going Green wrote about dishwashers today, check her numbers if you haven’t already http://burbanmom.blogspot.com
I do it a bit differently in that I start with an inch or two of soapy water and rinse over my dishpan. I save all my dishwater to flush the toilet and my hot water heater is set at tepid(or thereabouts). I usually toss the bottom cup or two of really scuzzy water although why i don’t just flush it all is beyond me. It can’t be too scuzzy for the crapper can it? Ok, no electricity used, about three gallons of water warmed w/ natural gas, no water wasted. Our counters are low as well and I am 6′3″.

[Edited by Will to add a link to Urban Mom's post about dishwashing]

]]> By: arduous http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-328 arduous Wed, 16 Apr 2008 17:33:44 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-328 Yeah, this is a great point. Something really big like a big pot, probably doesn't take much water to wash, and takes up a lot of space. OTOH, silverware is probably best off in the dishwasher. One of the keys though is this: if you handwash, handwash as SOON as you use the dish. It requires much less water than when the food has hardened. Also, now my head hurts from all the number crunching! ;) Yeah, this is a great point. Something really big like a big pot, probably doesn’t take much water to wash, and takes up a lot of space. OTOH, silverware is probably best off in the dishwasher. One of the keys though is this: if you handwash, handwash as SOON as you use the dish. It requires much less water than when the food has hardened. Also, now my head hurts from all the number crunching! ;)

]]> By: Student Doctor Green http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-321 Student Doctor Green Wed, 16 Apr 2008 03:13:29 +0000 http://greencouple.com/2008/04/16/running-the-numbers-on-dishwashing/#comment-321 Love the post! You are rocking with all this number crunching and home experimenting. Pots do take up too much space and I've often thought about hand washing them but I'd heard (as you did) that dishwashers were more efficient. I have an old model though so who knows what kind of efficiency or lack there of it has. I'm definitely going to dust off my drying rack and start washing larger items by hand. Love the post! You are rocking with all this number crunching and home experimenting. Pots do take up too much space and I’ve often thought about hand washing them but I’d heard (as you did) that dishwashers were more efficient. I have an old model though so who knows what kind of efficiency or lack there of it has. I’m definitely going to dust off my drying rack and start washing larger items by hand.

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