Dishwasher Uses Less Electricity and Water than Handwashing

tooblue on 24/04/2017 - 01:15

I often saw dishwasher and washing tablet commercials claiming dishwasher uses less electricity and water than handwashing. I find it hard to comprehend so I did a bit search.

First I was redirected to this Finish tablet website, claiming:

But a team of scientists discovered that dishwashers actually save you money, because they use a fraction of the electricity and water you’d need to wash the same load of plates by hand **.
** 2009 Colmar Brunton Study - Sydney

I tried to obtain the "2009 Colmar Brunton Study - Sydney" through the contact page. Unfortunately it didn't allow me to submit after I filled in all the possible fields, saying "Please answer all fields marked with *". Not to mention they miss the label "Phone" beneath the State textbox.

I then turned to Colmar Brunton. Oops, their "contact us" form at the bottom did't work either, erroring "Your message could not be sent, please complete all required fields and try again.", despite all possible fields had been filled out.

I tried these websites on two computers and three browsers. If a research company cannot get their website straight we can imaging the quality of the research they are delivering.

Personally I don't believe dishwasher uses less water than handwashing unless the family always have a dozen dishes to wash under maximum running hot water. In most cases cold water plus detergent is good enough. How does dishwasher beat zero energy consumption?

Why ain't these marketing driven research banned? Obviously most of these research are carried out with a set result.

How do you wash you dishes and do you believe the title?

Poll Options

  • 39
    Dishwasher uses LESS electricity and water for average family
  • 14
    Dishwasher uses MORE electricity and water for average family
Home & Garden

Comments

  • [Deactivated] on 24/04/2017 - 01:29
    +2

    having a dishwasher makes the wife happy, because she isn't the only one doing them.

  • retiredfeline on 24/04/2017 - 01:32
    +2

    Why not look at some other studies with figures and make up your own mind whether the claims stack up. Here's one by a green site which comes to the conclusion that you would have to work hard to make handwashing more economical than dishwashing:

    https://www.treehugger.com/kitchen-design/built-in-dishwashe…

    They quote 4-6 gallons of water for a full load. Now a full load is quite a lot of dishes, you would probably be able to fill two sinks. To most economically handwash that many dishes you would need a dual sink setup, one with hot detergent water and one with rinse water, and stay under 4-6 gallons.

    Personally I think there are many factors involved, such as the efficiency of the washer, whether you can choose a shorter cycle by prescraping the dihes, whether you make a full load before starting a cycle, how you go about handwashing, and so forth so the balance can tilt either way. And I think a dishwasher helps keep domestic peace, so it's more worthwhile instead looking at taking shorter hot showers.

    PS: Those are probably US gallons so * 3.79 to get litres.

  • Diji1 on 24/04/2017 - 01:48
    -5

    Dishwasher Uses Less Electricity and Water than Handwashing

    Hahahahahahaha.

    • Wystri Warrick on 24/04/2017 - 05:28
      -1

      HAHAHAHA YOU SAID IT MATE BAHAHAHAHAHAH

  • Euphemistic on 24/04/2017 - 06:28
    +8

    Our dishwasher uses around 12l of water. To fill the sink to a decent level (100ml) is about 14l of water (calculated by measuring). If I wanted to wash a whole dishwasher load in the sink it would take at least 2 sink fills becuase the water goes cold. Dishwasher uses less water.

    As for electricity, that's harder to calculate, but the dishwasher only heats the water it needs rather than a whole tank full so it's more efficient as a water heater, but does need to run the pumps etc so it could be close. The dishwasher will also only heat one lot of water where the sink will probably need two or three to do a full load.

    Then you add that a dishwasher can use stronger detergents than you use in the sink and also uses hotter water so everything is cleaner.

    I'm going with a dishwasher being much better for washing dishes and probably more efficient than hand washing.

    Additionally, the energy efficiency claim has been around long enough that surely it has been tested by someone that can be trusted. measure your own water and electricity usage and get back to us proving the dishwasher uses more water and electricity then.

    • Jabba the Hutt on 24/04/2017 - 08:57

      Closer to 10L to fill our sink to a decent level. But as in your case, no way that'd suffice for the equivalent of our typical dishwasher load - at least not without a serious 'yuck' factor. So let's say 20L. Then there's the rinsing.

      Bosch claims 12L for our dishwasher (Eco cycle), while Choice measured its use at 11L (Auto cycle).

      But the "fraction of the electricity" claim seems to be a stretch. Just lazily using these figures as a rough guide: our dishwasher uses 1.08 kWh (Choice) of peak electricity, or $108/year, while 20L of hot water from electric storage appears as though it could be about the same.

  • theHMASfriendship on 24/04/2017 - 08:28

    Our dishwasher uses more water than handwashing, but this is only because I hate handwashing and would rather build a mighty tower of used plates in our sink that at some point someone in the household sorts out, effectively rendering handwashing for me a zero water consumption activity.

  • iDroid on 24/04/2017 - 08:49
    +1

    For myself, my dishwasher would use less resources. I use way too much hot water catering for my excessive compulsive germ free biologically neutralised dish washing.

    My dishwasher gives me the same (deluded) impression of cleanliness with less effort and energy.

    As for the poll - If I vote for what I think an "average" family does is going to be pure speculative noise. I could vote for my usage patterns though!

  • Pumpkin_rrr on 24/04/2017 - 08:51
    +2

    I think you need to compare apples with apples. Granted, you can wash dishes by hand. But to reach the same level of "sparklingness", cleanliness, shiny etc, one needs to use more water and detergent, use more and hotter water.

    Also I hate drying dishes with towels. In fact I don't do that as I find its unhygienic. I'd rather air-dry when I handwash. So don't forget to factor in the cost & time of cleaning that towel :-))

  • eug on 24/04/2017 - 08:54

    I tried these websites on two computers and three browsers. If a research company cannot get their website straight we can imaging the quality of the research they are delivering.

    Hmm, all companies should have working websites, but why should a research company in particular be good at websites if they aren't selling their product with it (I'd imagine they do their business via industry contacts rather than random website visitors), or deal with the public at all? They're not selling tech, internet, web hosting, or anything website-related.

  • [Deactivated] on 24/04/2017 - 09:11

    In the old days it was true dishwasher used more water, and electricity. because the hot water from tap was inconsistent they didn't recirculate pouring water from tap and well people don't require electricity.

    Before I got a new generation dishwasher
    Sink washing
    I don't fill the sink but 2x 4 litre stock pots
    one clean (tap water)
    one rinse (filled with to 100C water from the 2000w kettle.),
    and then replace the water and repeat process

    so i estimate I need 12L - 16L water to wash + kettle 4 times + gas hot water, a good dishwasher is much better than I and certainly much better than a full sink of water.

  • slow on 24/04/2017 - 09:51
    +2

    I find one of the main advantages of a dishwasher is that you have somewhere to hide dirty dishes - the sink and drying rack is not constantly full of them. ie use plate, put it into dishwasher, where it can wait until it is full, and then turn on.

    I have an open plan kitchen and hate having to look at dirty and drying plates and dishes about as much as I hate having to wash them and put them away as soon as i use them.

    • eug on 24/04/2017 - 09:56

      I'd love to have two dishwashers. Take a plate from the first one, use it, then put it in the second. Once the second fills up, run a load and repeat in reverse.

        • eug on 24/04/2017 - 10:07

          My friend had a drawer-style one. There really isn't much internal room. Two full-sized ones would probably be more practical than two less-than-half-sized ones.

        • John Kimble on 24/04/2017 - 13:59

          @eug: How big is your kitchen!?

        • eug on 24/04/2017 - 14:11
          +1

          @John Kimble: I'd love to have, not I love my... :)
          Don't forget that if you're using one dishwasher for dish storage, you'll need one less cabinet. Almost.

  • bonezAU on 24/04/2017 - 10:12
    +1

    Dishwashers definitely use less water than hand washing, but assuming everyone uses electricity to heat their water is a bit wrong. In the past 15 years I have had either instant gas or gas storage* at every house I've lived in, so the electricity thing really is a moot point in this case. I guess you could say I have the kitchen light on for longer while standing there handwashing the dishes than I would if I just pressed a button and walked away then turned the light off…

    I've also never had a dishwasher in the last 15 years at any house I've lived in, but am soon to buy my own home and it will be the first thing that gets installed.

    I still agree that overall dishwashers are cheaper to clean dishes than doing it manually, and I can't wait to get one.

    *Gas is still reasonably affordable here in WA because we aren't facing the shortages the rest of the country is

  • mbck on 24/04/2017 - 12:08
    +1

    Question is what's their methods of hand washing? Fill up 2 sink full of hot water and replace after 5 plates? While the dishwasher group is on super saver mode?

    • psyren89 on 24/04/2017 - 13:09
      +1

      Wet sponge, add detergent, scour dishes (wetting minimally as necessary).
      Stack dishes in sink and rinse when done, all using cold water.

      I never got why people need to fill up a sink, especially with hot water - dishwashers can use water with a sustained temperature hot enough to kill bacteria, whereas trying to do the same with hand washing will just burn your hands off.

      I realise a case can be made for dishwashers being able to properly sterilise crockery with hot water, but with proper hand washing (assuming you don't leave any oil/food to which bacteria can cling), by the time your dishes dry, surely it should be too dry for any bacteria to survive?

      • John Kimble on 24/04/2017 - 13:55
        +2

        I never got why people need to fill up a sink, especially with hot water

        I find some foodstuffs come off easier in hot water. If you use gloves the temperature has less of an impact to your hands.

        • psyren89 on 24/04/2017 - 14:32
          +1

          I find some foodstuffs come off easier in hot water.

          True, soaking has its use, but I think that's more reserved for baking trays, pots/pans, etc. immediately after cooking, as opposed to bowls or plates.

          If you use gloves the temperature has less of an impact to your hands.

          The tradeoff is not being able to feel food stuck to whatever you're washing.

      • mbck on 24/04/2017 - 14:29

        If it's something sticky, I would just cover it with water and detergent (not the whole sink, but just the surface area of the plate/bowl. I'll leave it overnight if required.

        Then do as you would do "wet sponge, add detergent…"

        Done in <10 minutes.

        Dishwashers takes at least 36 minutes on my ecomode. And it will still leave some bits that you'd still have to manually clean off. Plus with this ecomode it feels like there's still some residue detergent left (using Finish). So I'd still need to do some rinsing.

        The only great thing I can think of with dishwashers, is time efficiency. You put everything in, it does it's job, while you are free to do anything you want. I personally don't believe they save more water/energy; I think that's b0ll0cks.

  • JimB on 24/04/2017 - 13:40
    +2

    Without a doubt a dishwasher uses less water.

    It's unlikley that it uses less electricity.

    For the convenience and getting a dishes/cutlery much cleaner, dishwashers is much better than hand washing.

    • John Kimble on 24/04/2017 - 13:57
      +1

      I agree, but sometimes my dishwasher doesn't clean first go or has detergent streaks still. Have to run it again or hand rinse so negates any "savings". Annoying!

      But I think it's getting on, so might be time for another one soon…

      • JimB on 24/04/2017 - 14:20
        +1

        Perhaps you need a better dishwasher or try a different detergent.

        The only time it doesn't clean first time is if the plate/cutlery has really hard dried on food scraps or user error- plates arranges touching each other.

  • Archi on 24/04/2017 - 13:43
    +1

    sometimes it's not about which one uses less water or which one is more energy efficient.

    I couldn't care less, I know mine is rated well. I pack everything in there I turn it on… and I go play with my daughter for the limited time she is awake when I get home from work.

    I have a dishwasher, but sometimes I will choose to wash the dishes by hand because I want to get away from the kids for 30 minutes.

    why does it have to be an argument on what is better,

    it's all relative on how you want to spend the time

  • Archi on 24/04/2017 - 14:17
    +1

    also depends on what you are washing. what type of cuisine that has been cooked and who cooked it, what types of dishes you own more glass, or ceramic, or porcelain, or stainless steel.

    also depends on the people you live with. are they going to mix non oily items in the sink with oily items. for example, have baked on pasta dish soaking in the sink to loosen up the burnt parts.. and along comes room mate and tosses a glasses they have drunken water from into the sink. you cant foresee 'STUPID' sometimes.

    usually the person washing the dishes will cook in a way that it makes it easy to clean. use the right tools for the right job.

    oily food on glass is easy, oily food on plastic not so easy,

    non oily dishes or cups are quick with cold water and soapy sponge.

    baked on pasta on an oven dish wont come off easy washing by hand or machine.

    pots and pans will differ to cups and glasses, knives and forks differ to chopsticks.

    way too many variables.

    • John Kimble on 24/04/2017 - 15:06
      +1

      Yes, my wife insists on putting the plastic takeaway containers in the dishwasher as they are hard to handwash. Only thing is sometimes they flip over at some stage of the cycle and just fill up with (soapy or dirty) water. Other times they warp and are useless from then on too.

  • Boshait on 24/04/2017 - 22:01

    I don't understand why most posters are arguing about the amount of water used. The cost of the water is negligible so that can be ignored. From a cost perspective the comparison the things to consider are the cost of the dishwasher, the electricity it uses and the consumables such as detergent. It would be astonishing if hand washing was not far cheaper.

    • eug on 24/04/2017 - 22:24

      Are you calling Boshait on the dishwasher manufacturers' claims?

    • retiredfeline on 25/04/2017 - 00:43

      It's the amount of water that needs to be heated, hence the bulk of the electricity cost. Comparing hot with cold washing isn't apples with apples.

  • Cleremy on 24/04/2017 - 23:41

    I knew a single middle aged mother who had a working dishwasher in her kitchen (rented house) but wouldn't use it because she believed handwashing was more economical. The "somewhere to store dirty dishes" argument is one I hadn't thought of before. This person's kitchen was full of dirty dishes to one side, and washed dishes to the other side stacked as high as they safely would go, plus second near-permanent pile of washed dishes besides that on a tea towel.

  • altomic on 25/04/2017 - 12:42
    +1

    I use a dishwasher now because i am time poor (need time to look for bargains) but when I occasionally hand wash I add ~a litre of hot water and add detergent to that. then leave the tap on a strong trickle. wash dirty dishes in hot detergent water and rinse under the trickle. the trickle water adds to the detergent water and is clean coming out of the tap.

  • Ozvalue on 07/05/2017 - 22:22
    +1

    Time is money my friend

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