While there appears to be hundreds of references in a Google search about dishwashers being more efficient than hand washing, all those sites seem to be merely cloned version of the same comments (usually with plenty of embedded links to buy or install dishwashers). Just like the repetitious claim that the average dishwasher uses 15 gallons of water. But I finally ran across an article in the UK Guardian which also questions the practical comparison of bad hand washers to super efficient machines.
You can read that article here: http://www.guardian.co.uk/g2/story/0,,1605710,00.html
And then there is a nice little story and study done by Ask Pablo. He has all the numbers and details including the name and model of the dishwasher he used in a more realistic setting. You can find his story here:
http://www.triplepundit.com/pages/askpablo-the-dishwasher-002386.php
I'm not out to kill the dish washing machine. I really just want people to be more efficient about their choices and how they use them. We won't always have the time to be more efficient. Nobody is going to try and tell us that driving a car is more efficient than riding a bike. We know it uses a lot of energy which translates into more pollution etc. But there are times when we can make a better choice and we need to exercise that option.
Sunday, March 18, 2007
I find that dishwasher report from Germany
Seems I hit the mark with my last paragraph of my last post. We don't use a dishwasher because it is more efficient, we use it because it is a convenience. In this case, the testers did use those twelve people from my party or as they put it, twelve place settings comprising 140 pieces. So if you have a family of four and you eat at home for all three meals and you always have a complete formal meal with a dinner plate, salad plate, soup bowl, dinner fork, salad fork, teaspoon, soup spoon, knife, water glass, coffee cup/wine glass and various cooking utensils, then I think you should use a dishwasher just so you can spend more time with your family. Then again this kind of formal eating at every meal would probably mean you have a butler and maid preparing and serving your meals for you and you don't care whether they wash the dishes or a machine does.
Go look at your own cupboard. I would have empty mine out and I still could not come up with 12 place settings. I would run out of dishes first and.... a OH... I'd have to wash dishes after lunch just to have some for dinner. But that's the Achilles Heel of the dishwasher, it must be full to claim it is more efficient because it uses the same amount of water each time. A hand washer only uses as much water as is needed to clean the dishes on hand.
This report used an unnamed model of dishwasher to square off with randomly picked people from different countries in Europe. The biggest problem may simply be, as this study showed, that hand washers are notorious for letting the hot water run the entire time they are doing the dishes. How else to explain the average use of 27 gallons to wash these dishes? But then how many people leave this many dishes to wash till the end of the day. Which is another flaw in the study. Unless you actually have a party, you'd have to let the dishes sit around all day until after dinner by which time anything on the breakfast and lunch plates will have dried to a nice diamond hard consistency. Unless you rinsed them off....opps... wait! No rinsing, remember? And as I mentioned in the previous post, anyone whose used a dishwasher knows about the inspection process afterward to make sure the dishes are really clean. Even more interesting though, go look at your own cupboard.
While the report doesn't mention the name brand of the machines used, it does claim they did a load with only 4 gallons of water. That is pretty impressive except I can't find any model that makes that claim. It seems that in the United States the newest most efficient models are still going to use about 8 gallons of water on the most efficient settings.
As you'll recall from the previous post, I got off on this post because of the comment from CNN about dishwashers being more efficient. But nobody at CNN read the report. They did like the rest and just read a sound bite from some other source without finding the origin of the study. But now this statement can be found all over the Internet with some at least crediting the University of Bonn for the study. But they still didn't read it or they'd wonder about what kind of person uses almost 30 gallons of water to wash a load of dishes or who could let 140 pieces pile up before washing them (try and picture that).
Here is the link to the University of Bonn study: HERE
Saturday, March 17, 2007
Dishwasher vs Hand Washing
I start off this blog today after listening to a "Tip of the Day" from CNN. Some report I have not been able to get my hands on published out of the University of Bonn, Germany, claims that dishwashers are more efficient than washing by hand. I guess this might be true if you are using an expensive brand new dish washing machine with super efficient technology and comparing it to a hand washer who lets scalding hot water run full blast the entire time they wash dishes.
This isn't about convenience. If your dishwasher can do the job without any rinsing or second cleaning, than it will save you some time but not money or energy
First off there is no contest if you don't already own an efficient model. The cost to manufacture, transport, and install a new machine will never be recovered. The machine will need service or have to be replaced long before any energy savings could be realized. Dishwashers use electricity to operate and gallons of burning hot water to do their job. I don't know about you, but I don't fill up my sink to wash dishes. I wash them, rinse them, and I can do a whole sink load with only a couple of gallons of water and a few drops of liquid detergent. I don't let the faucet run the whole time and I don't need hot water because I do the cleaning, not 140 degree water shooting out of high pressure nozzles. My sink will never break down or need repairs. I have replaced the water valve in the faucet body one time in 30 years, with a free unit from Delta Faucet who guaranteed the faucet for life.
If you already have a dishwasher installed you can at least try to compare the efficiency of the two methods of cleaning those dishes. As anyone has learned from using a dishwasher, the ability of a machine to do a good job of cleaning is based on how dirty those dishes are to start with. It also matters how well that unit works. Just looking over the reviews from buyers at www.sears.com reveals how poorly the cheaper models perform. A hand washer scrubs that one dish till it's clean because that dish is being visually inspected during the whole process. A machine just assumes that enough hot water squirting long enough will have done the job.
The efficiency of these methods really comes down to how much water is needed since the keyword here is how "hot" that water is. A dishwasher needs water at 140 degrees Fahrenheit to do the job as designed. So the first thing you need to do is turn your water heater up because few people have their heaters set this high. Of course having this water set this high also causes the 300 emergency room visits each day by children burned by household water. Turning up the water heater is also going to use more energy which isn't necessary when washing by hand.
Some models have heat boosting modes. This allows you to set your water heater back down to a safer temperature of 120 degrees. But the water heater doesn't care where the water is going. Once water leaves the tank the heater kicks on and starts heating up that incoming water. Add to that the energy used by the dishwasher to heat the water up to 140 degrees using its booster and the savings isn't going to be very much and it isn't using any less water. But this brings up some interesting things about a dishwasher. If it is so efficient why do I have to select all the most efficient options to make it efficient? If I select all these efficient modes will the dried on egg yolk come off? One of these options is the heat dry mode. Don't use it if you want to save some energy but it still uses electricity to blow air.
Then there is the claim that the detergent used in a dishwasher is also cheaper; ABSURD! A few drops of any dish washing liquid on a sponge will wash an entire sink of dishes. A bottle of dish washing liquid from Walgreen's can cost only $1.50 for a 13 .oz bottle while an 8 oz. packet of Cascade for a dishwasher also selling at a Walgreen's is $4.00 and that's for 12 wash cycles. You do the math.
If you really want to be efficient you will simply wash your dishes by hand and do it right after each meal if time allows. You don't need to wait for a full load like a dish washing machine, you won't make nearly as much noise, and as long as you pay attention you won't be inspecting any dishes to see if they got cleaned right the first time. If you have a machine save it for that party when a dozen people come over and you've got that pile to do but not the time.
First off there is no contest if you don't already own an efficient model. The cost to manufacture, transport, and install a new machine will never be recovered. The machine will need service or have to be replaced long before any energy savings could be realized. Dishwashers use electricity to operate and gallons of burning hot water to do their job. I don't know about you, but I don't fill up my sink to wash dishes. I wash them, rinse them, and I can do a whole sink load with only a couple of gallons of water and a few drops of liquid detergent. I don't let the faucet run the whole time and I don't need hot water because I do the cleaning, not 140 degree water shooting out of high pressure nozzles. My sink will never break down or need repairs. I have replaced the water valve in the faucet body one time in 30 years, with a free unit from Delta Faucet who guaranteed the faucet for life.
If you already have a dishwasher installed you can at least try to compare the efficiency of the two methods of cleaning those dishes. As anyone has learned from using a dishwasher, the ability of a machine to do a good job of cleaning is based on how dirty those dishes are to start with. It also matters how well that unit works. Just looking over the reviews from buyers at www.sears.com reveals how poorly the cheaper models perform. A hand washer scrubs that one dish till it's clean because that dish is being visually inspected during the whole process. A machine just assumes that enough hot water squirting long enough will have done the job.
The efficiency of these methods really comes down to how much water is needed since the keyword here is how "hot" that water is. A dishwasher needs water at 140 degrees Fahrenheit to do the job as designed. So the first thing you need to do is turn your water heater up because few people have their heaters set this high. Of course having this water set this high also causes the 300 emergency room visits each day by children burned by household water. Turning up the water heater is also going to use more energy which isn't necessary when washing by hand.
Some models have heat boosting modes. This allows you to set your water heater back down to a safer temperature of 120 degrees. But the water heater doesn't care where the water is going. Once water leaves the tank the heater kicks on and starts heating up that incoming water. Add to that the energy used by the dishwasher to heat the water up to 140 degrees using its booster and the savings isn't going to be very much and it isn't using any less water. But this brings up some interesting things about a dishwasher. If it is so efficient why do I have to select all the most efficient options to make it efficient? If I select all these efficient modes will the dried on egg yolk come off? One of these options is the heat dry mode. Don't use it if you want to save some energy but it still uses electricity to blow air.
Then there is the claim that the detergent used in a dishwasher is also cheaper; ABSURD! A few drops of any dish washing liquid on a sponge will wash an entire sink of dishes. A bottle of dish washing liquid from Walgreen's can cost only $1.50 for a 13 .oz bottle while an 8 oz. packet of Cascade for a dishwasher also selling at a Walgreen's is $4.00 and that's for 12 wash cycles. You do the math.
If you really want to be efficient you will simply wash your dishes by hand and do it right after each meal if time allows. You don't need to wait for a full load like a dish washing machine, you won't make nearly as much noise, and as long as you pay attention you won't be inspecting any dishes to see if they got cleaned right the first time. If you have a machine save it for that party when a dozen people come over and you've got that pile to do but not the time.
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