Dishwasher versus Hand-Washing

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What about a machine that hand-washes the dishes?Let’s say you’re about to clean your dishes, and you want to do it in the best way environmentally possible. So do you use your energy-efficient dishwasher, or do wash your dishes by hand? It might seem like a simple question, but man oh man there are a lot of answers (and a lot of other websites which have covered this question, with one result or the other). I’ll try to look at both sides of this surprisingly heated debate.

Water Use

A modern dishwasher will use less water than you would if you hand-washed your dishes. But this is assuming that you hand wash your dishes several times a day instead of leaving them in the sink for a “big wash”, which I always end up doing. This also assumes that you don’t use too much water pre-rinsing the dishes. So basically, it all boils down to efficiency of scale (doing a large load is more efficient than doing many smaller loads of dishes). If you only do large loads and moderate your water use, hand-washing is more efficient. But the smaller your loads are and the more water you use, the bigger the advantage of using a dishwasher.

Energy Use

Most of the energy for washing dishes (whether by hand or by dishwasher) comes from heating up the water (unless you like to wash your dishes with ice-cold water). Obviously, the dishwasher uses some electricity on top of that, so hand-washing wins this battle.

Time

Dishwashers will save you time. Just put in some dishes, turn it on, and walk away. But sometimes you open the dishwasher when it’s done, and some of the pans and dishes are still dirty. The more that happens, the smaller the time advantage that dishwashers have.

Overall Environmental Impact

Hand-washing wins this one. There are phosphate-free soaps available for dishwashing or handwashing, but the energy and materials used to make a dishwasher is considerable. Plus, dishwashers take more energy, sometimes use more water, and sometimes even take more time. So unless you are doing a huge load of dishes (or unless you work in a restaurant), then hand-washing is the way to go. So put on them yellow gloves, fill up a pot with hot, soapy water, and get ready for some good ol’ hand-washing.

Posted in energy conservation, water on Tuesday, October 16th, 2007 at 10:13 AM.

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Garrett Johnson's avatar

Garrett Johnson · 887 weeks ago

I've pondered this same question, so I looked at other sites with scientific evidence. The dishwasher seems to win hands down.
2 replies · active 852 weeks ago
You're right. "Handwashing wins" is based on opinion and guesstimates. Methodical studies show otherwise. Two things never mentioned by people who say handwashing is best as long as you do one batch and leave the dishes soaking all day: if you do the equivalent of a dishwasher load, you'll have to change that sink water at least once; and don't people ever RINSE dishes? that running water (at least warm or most people) undoes all your handwashing savings.
It all depends on how new (and efficient) the dishwasher is, and how the dishes are washed by hand. If you leave the water running the whole time you're rinsing dishes, then yeah, that definitely uses a lot of water.
Also I clean off as much of the crud I can get off the towel in the dirty sink water left in the wash sink. That way I dont have to worry too much about the towel getting food or anything like that in my clothes washer.
Assuming that most people rinse dishes before putting them in the dishwasher, I have no doubt that handwashing (without keeping the water running, of course) uses less fossil fuel energy, and probably less water too. If the dishes were just used, they need not be soaked, and so a sponge with some soap and water works great. Filling up the sink is not necessary.

If one has a large load, the dishwasher might well be better, or at least more efficient.
It looks like scientific research is on the dishwasher side, but they usually don't consider the materials used to make it and the disposal of it. I can see that if you follow the best method in an Energy Star dishwasher how it can be better, but living in an apartment - the dishwasher is very old.

When the machine is older; it's not as functional, definitely doesn't do a good job and I think has a worse effect on the environment. You usually have to pre-wash your dishes, then to run the machine - more work and more energy wasted. I find in this case I was by hand and then place the clean dishes in the dishwasher to air dry. That way you don't need to buy a rack and I don't get spots on my clear glass dishes. And I'm buying an aerator to limit my water usage tomorrow. Great information from everyone.
It seems like everyone is forgetting to mention the cost of soap. Dishwasher detergent is far more expensive than dish soap, and you use more of it also. That is the main reason we started handwashing all of our dishes.

Also, most of these studies are assuming that you will put all of your dishes in the dish washer and never have to hand wash. Unless you buy a top of the line dishwasher, there are some things that will just never get clean in your dishwasher and you will have to wash them by hand any way. Even if we did use our dishwasher, we would still have to hand wash every day to clean the really caked on stuff, so why not wash them all while we're at it.
1 reply · active 827 weeks ago
Wow, you based the handwashing/dishwasher decision on the cost of the soap? Do you realize how many loads you get out of either purchase? It comes down to mere cents per load, whichever way you go. So, science shows that a dishwasher is more efficient, but it's worth $0.08 per load to you to stand at the sink for 30 minutes instead?
Mommyfrugal's avatar

Mommyfrugal · 848 weeks ago

After reading I want to know is there any study that show hand washed is cleaner than machine washed? or vise verse .

When it come to our old apartment washer ;it doesn't do a good job. so we end up pre wash and clean some glasses or dishes that have been already washed by the washer.

In addition the dish washing liquid or gel for the washer is more expensive than the dish soap .

I prefer to hand wash but if its not as sanitized as the dishwasher .I might go back the the dish washer even though is as time consuming as the hand wash.
Let me be more specific with the article.. draw your own conclusions (energy efficiency, etc.), but I think that it is pretty disgusting to keep dish water around, seriously germs are one of the things that cleaning is about and adding germs to your dishes is less than ideal. To be honest, I do both though, with small loads wash by hand, medium-to-large loads I use the dishwasher.
OK, enough discourse, here is the link:
http://www.landtechnik.uni-bonn.de/ifl_research/i...
what about the true cleanliness of the dishes? which is healthier to eat off of? I'd bet the dishwasher kills more germs --which is why if there is some sick in my home I use the dishwasher. Just wonder if anyone has done a study ?
Has anyone calculated the full environmental cost of using a dishwasher--the materials used ot manufacture it and then disposal of the machine when it breaks down--considering that most kitchen appliances are now made to last for about 5 years or less? If you do not scrape or rinse your dishes before putting them in, the dishwasher breaks down even sooner. I would like to know if hand washing is more environmentally friendly than using a dishwasher given the planned early obsolesence of dishwashers.
1 reply · active 795 weeks ago
That's a good question -- I didn't think about that side of its environmental impact, but it'd definitely affect its "greenness". Kudos to you, KTL, for pointing that out.
Best you should edit the page subject title Dishwasher versus Hand-Washing | Green Thinking for the Average Joe to more catching for your blog post you make. I liked the post still.
I’d go for hand-washing anytime. Apart from being more “green”, it’s also a good way to exercise my arms!
It’s really a battle between the conventional and the convenience. Some of these kitchen appliances saves us some valuable time but we neglect the impact it has on our environments.
I used to have a dishwasher but it costs so much money to run I decided to go back to hand washing my dishes which costs nothing and good for the planet.
One of the most important benefits of hand washing is that you can collect the water in a tub & use it for watering the garden (just use gray water safe soap) or keeping the compost moist. Dishwashers waste the water, a precious resource!
1 reply · active 644 weeks ago
As long as your soap is safe for plants and such, I wholeheartedly support your advice.

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