CHOICE membership

Dishwashers vs hand washing - which is the most efficient?


#1

A dishwasher can save you time, but what is the cost in energy and water compared to some good old elbow grease for a typical pile of dirty dishes? Some say handwashing works the best, but others will swear by their trusty dishwasher.

Help us solve this conundrum and enter our MythDefied competition for your chance to win. Make sure you leave comment before the comp closes on Friday 8th of June to be included for chance at the prizes.


#2

Oh dear! I don’t know if this is the sort of reply which you are seeking; but here I go, onto my soapbox. Decades ago we bought a highly-recommended dishwasher, an Indesit, which from memory was called a ‘potscrubber’. That was in the 70s and 80s when we were young and childless and heavily into dinner parties with friends; so we thought that a dishwasher would be a boon. Well, very quickly we learnt that we had to rinse and scrub off every bit of food before we put it into the dishwasher, because otherwise lots would bake onto the finally washed products. And it would take ages to pack it correctly according to the instructions. And crystal glassware would be ruined if washed in it. And we found that the potscrubber did not scrub them at all. And after a dinner-party when we loaded it up and switched it on to work whilst we slept. Well, the NOISE from this thing operating, kept us awake. So no gain there. I also resented that it had no facility to use hot water from our off-peak hot water system, so we had to pay full electricity prices for it to heat up all hot water itself. grrr…
When we moved house, the new one, on purpose, had NO dishwasher.

Roll on a few decades, another house move, and old age; and my wife decided that she wanted a modern dishwasher. I disagreed. She won out of course and bought a new one, a high-end brand. Well, I am disgusted that in those intervening decades they still have not engineered it to use hot water from our off-peak hot water system; my wife seems to have great difficulty in stacking it according to their complicated rules; and when it is opened after washing, many items still have lots of water droplets on them, especially plastic items, and saucepans; and some storage plastics have melted. BUT it is quiet and does not disturb our sleep.

Okay, there is the belly-aching. Now for the advert claims: they claim that a lot of water is saved by using them. I have not bothered to measure it, but I would doubt that they would be as frugal with water as I am with my hand pre-rinsing; dishwashing; and suds rinse-off afterwards.

But most of all, I am just disgusted that these highly-touted high-end imported brands (they probably are all imported anyway), have not been engineered in an age of renewable energy being used in home hot water systems, as well as the more traditional off-peak cheaper hot water systems; to use the home hot water system. My feeling is that the prices have skyrocketed over the decades, but the technology seems to be much the same as it was way back then.

My apologies if this rant has been more off-topic, than on it. Cheers.


#3

I’m basically lazy. I hate housework, and all that goes with it. So I thought I might like a dishwasher. Then I thought again and decided against. I cant stand up for very long without getting a backache, so I do the dishes in stages. And theres only one of me, so I confess to doing a rinse but not a proper wash except once a week. I think I probably use less water, but who knows… I’m saving electricity and the initial cost of the dishwasher. All good.


#4

No offense to anyone - It all depends on who it is does the dishes.

It also depends if you accept or reject other factors such as saving time or saving the planet (sustainable outcomes). Are these how efficiency should be assessed. Improving productivity and increasing consumer spending are some of the corner stones of our current government. On that basis the dishwasher wins - no need to look here!

Time saved, water used, energy (electricity/gas) used, cost of cleaning products, environmental costs/outcomes, health risks. It’s more than just water and power. In the hands of the right users both options may produce acceptable results, just as both hand and machine can also produce poor outcomes.

Observed varying behaviors of others and a good dose of TV advertising on how to better wash dishes suggest many variables in any situation.

I’ve observed for those of us who wash dishes by hand:

  1. some of us may not see well, wash casually and put away stained or dirty dishes as the norm, (a health risk as the pates etc still appear clean, if as for any person saving power by leaving the lights off or missing their glasses)

  2. some of us follow the golden rule of always having a foot of suds in the sink and use ten times the volume of detergent needed. (major down steam impacts but great for my Unilever share value)

  3. some of us follow the latest TV trend of using a refillable detergent and sponge wand to hand wash under an open sink as the hot water cascades over the plate and down the drain leaving a sparkling clean plate. (oh how our shares love that!)

  4. some of us wash in one tub and rinse in a second full of water while others leave the tap running continuously in the second tub to rinse more directly.

  5. some of us are on tank water and have on site disposal systems that need special TLC with what we put through them

  6. some of us wash in water that is near scalding (no tempering valve!) and others in luke warm water.

It would be good to see a base set of tests on hand washing costs and time taken to understand what the relative merits of each approach are. Unilever may even be able to help retrain Choice staff in the best method!

For those of us that use dishwashers there may be just as many variables to consider.

  1. some of us put everything in the dishwasher and turn it on several times a day

  2. some of us save a wash until the dish washer is full

  3. some of us hand rinse and scrape under a running tap before using the dish washer, others don’t

  4. some of us split our work load and do the bigger and dirtier items by hand

  5. some dishwashers can be connected to the HW supply to save on time and the cost of electricity to heat the water in the washer

  6. some of us have solar HW or power or off peak HW or gas HW or … The cost of heating the water for a wash in a dish washer depends?

  7. for some the relative cost of power in the same household may not affect a comparison although it is somewhat easier to leave the dishwasher cycle on timer till noon when you many have a surplus of solar electricity vs when you are home at night and only have full cost mains power if you wash by hand

  8. some of us use a one for all tablet every wash no matter what the load while others use a powder.

  9. some of us may be very frugal with our powder and use one that has less environmental impact

  10. some of us may use salt with our dish washer

  11. some of us may add a freshener and put a cleaning agent for the dish washer through a cleaner only dual cycle

As for our own experience for 2+ we use a dishwasher once a day with minimal pre-cleaning of plates. We wash all heavier and dirtier items by hand as needed. As we are on tank water with on site grey water absorption trenches we are very frugal with detergents. On assessment the water used by the dish washer is far less significant than other household needs, in particular if you wash by hand three times a day to avoid a kitchen piled with dirty plates and dishes. Our HW is on instantaneous gas (bottled) so it is unlikely the differential cost of heating the HW for hand or machine is significantly different for a similar volume used.

Any assessment of efficiency is less meaningful when it is not a direct comparison with how a household functions. There is no such thing as a typical household any more? What about using only paper plates and putting them out to mulch?


#5

Eh? I’ve connected ours (quite an old model) directly to the hot pipe, so it cant use anything other than pure solar heated water from our solar (no gas or electric booster) HW system. If there happens to be too much cold water in the pipe at the fills for the hot water washing and rinsing, then the PV panels and battery supply the energy to bring it up to temperature. IE, every wash is 100% powered by solar power. That can be the case with any brand or model of dishwasher.

However, it does use more water than washing by hand, so is only run with full loads, as water is currently rather scarce.


#6

I often question the water use reported by many diswasher manufacturers, here is one by Bosch.

Bosch claims that a dishwasher can save up to 12000L per year (or about $30 in water) compared to using a diswasher 4 times per week. Now does this number doesn’t stack up…

An efficient dishwasher will use about 12-15L per cycle, lets assume the 12L used which is also quoted on the Bosch website. This 12L is assumed for a light load (where plates etc are not heavily soiled). This corresponds say to about 50L per week or 7L per day. This 7L also assumes that plates are not pre-rinsed…something which may be an issue if not done and dishwaster only used very second day (we will ignore this ‘fact’).

Now, 12,000L corresponds to about 33L per day or 11L per hand wash.

Now, it is a saving or 12,000L, so one must also add the water used by a dishwasher. usage (around 2-3 L per meal equivalent) This means that dishwashing would use around 13L per event/after each meal. This is a 10L bucket and a half of water.

Our kitchen sink has a volume of about 13-15L…so the savings quoted by Bosch and many other manufacturer’s assume that we fill the sink up to the brim in order to wash the dishes…which would make hand dish washing impossible unless one makes a mess in their kitchen.

Now, these marketing/advertising claims have been tested and can be found here. It was found that these claims were not misleading.

I wonder if they are misleading when the numbers are supported by a Colmar Brunton study (which is a marketing and market research company) in May 2009 also seem a little unrealistic. One such claim which seems unrealistic is …On average, it took 75.11lL of water to hand-wash a 12 place dinner setting (132 individually soiled pieces). By comparison, the Products use 13.6L to wash the same 12 place dinner setting, equating to a saving of 61.51L per wash. For a 13L sink, this means one would need to empty and refill between 5-6 times …I am yet to do such after any dinner party we have. we may do it twice if the food was a little oily/fatty.

I suppose over two days one might generate 12 place setting work of plates (assuming on two in the household), but again, a dishwasher wouldn’t also be able to handle the glasses (12 at least), mugs (could be 4-6), saucepans, frying plans/wok (okay, woks don’t go in dishwashers so one would heed to add the hand washing water to that of the dishwasher), cooking utensils, cutlery (12 place steeing worth (the test famiky must be wealth to have 12 cutlery setting lying ajd), sharp knives, cutting boards (whoops, again these don’t in the diswasher) etc.

I wonder if many of the saving claims by the dishwashing manufacturers are realistic or based on a worst case, OCD type scenario. Maybe the modelling of water use was for a couple that has big dinner and cutlery sets, tends to buy precooked foods (either bought as hot or only requiring reheating in disposable packaging) for most meals. In such case, the use of mainly plates, cutlery and standard glassware, the dishwasher may be more efficient if the residence was connected to reticulated water and mains electricity.

I think that the efficiency of diswasher’s is over stated, especially when one may use solar hot water for hand washing dishes and/or use tank water.

It is also over stated if one uses a range of kitchen items that it is not recommended to be dishwashered (sharp knives, zinc/silver/gold metal plated items, crystal etc) or it is impracticable to dishwash (e.g. large saucepans or large cutting boards)

The claims seem a little dubious to say the least.

I expect that every individual household would have different dirty kitchen items/dishes so it is very hard to say which method is more efficient.

My own observation possible indicate the following:

  • if one mainly eats out, then possibly the dishwasher is more efficient as it would be used less, but hand washing would be still regular is one wishes to keep the kitchen looking clean and tidy.
  • if one buys precooked meals (either hot or to be reheated), then possibly dishwasher as it would be similar to the first point.
  • average household that eats out 2 or less times per week and prepares home cooked dinners, then hand washing is likely to be more efficient. If the house is on PV solar and tank water, and dishwasher is used when the sun shines, then it could be argued that the dishwasher may be more efficient (namely use less of resources one may pay for).
  • If one only cooks ones own meals, see dot point 3.

It is also worth noting that for large households, any dishwasher advantage over hand washing would be less as one would need to run a dishwasher at least daily and the dishwasher running costs, water and energy use would be more than that stated for a light load/use scenarios.

I still plan to mainly hand wash and use the dishwasher if we have a large dinner party and one doesn’t feel like washing everything up after the guests leave (even though some hand washing up is still required).


#7

It’s good to see that efficient use of Time (convenience) can be a consideration.

Choice’s efforts to provide great consumer advice on which dish washers are the best buys is valuable.

Knowing how well dish washers perform in different scenarios when compared to manual options may also serve a purpose in telling us how effective a dish washer may be.

In other practical terms the perceptions we have or the facts may not matter to most of us. It is a more efficient use of energy and less carbon intensive to walk to public transport and catch a train than to drive door to door. Mostly!

Most of us still choose to drive because it is more time efficient. In considering washing up the behavior is the same.


#8

I would like to contribute some highly reliable anecdotal information…

We have a dishwasher, but hardly ever use it. Mayhaps twice a year.

My experience is that if we place dirty glassware, crockery, and cutlery into the dishwasher they don’t come out as clean as if I hand wash. Inevitably there are lip marks on the glassware, and food detritus on the c & c.

If the cutlery & crockery are accumulated in the dishwasher to wait for a full load without first rinsing everything, the food hardens and won’t come off during the wash.

Pots and pans take up too much space and often come out looking the same as when they went in. Therefore it is essential to scrub pots and pans first. So why bother putting them in to the dishwasher?

Finally, long stemmed glassware, or crystal is definitely a no no in the dishwasher unless of course you don’t like it and want to reduce their number.

This means that you are already rinsing, and cleaning tableware and cooking utensils because of limitations of the dishwasher. So, you may as well as just keep going and clean everything manually.

I sluice everything off first quickly with a very small amount of water to remove the majority of loose gunk. Then it’s to washing up with a very small amount of water in the sink with detergent sing a soft scourer. (I believe that the mechanical action using a scourer is important to clean everything off properly.) I wash and rinse the detergent off into the same sink.

Any non oily/greasy things come next, and then gradually progress through the more and more dirty/oily/greasy items. This ends up using no more than a sink full of water. and everything is sparkling.

If you want a job done properly, you have to do it yourself.


#9

In my opinion you need a better dishwasher as we use a Choice recommended Bosch dishwasher and Choice recommended ALDI dishwasher tabs and the result is always perfect with never a mark remaining including always removing cooked on food from pots and the glass ware and cutlery is always comes out bright and shiny like it has been polished.

In my opinion I don’t care if the dishwasher is less or more water and energy efficient as it will always get the job because if it doesn’t do it I have to do it and I hate doing it.

BTW most recent dishwashers use the heated water from the previous part of the cycle to heat the water in the next part of the cycle via a heat exchanger so they save even more energy.


#10

I hand-wash stone cookware in order to preserve the coating and because they’re easy to clean. Everything else goes into the dishwasher.

I don’t like the strange metallic odour on cutlery that has been hand-washed - no matter how thoroughly - and air-dried on the dish rack.

The dishwasher cleans beautifully. Glasses and other dishes come out sparkling and smudge-free. After reading a Choice article on dishwasher tabs, I use the Aldi platinum tabs. Also, I always use a heavy-load cycle on the dishwasher so it’s not the most economical approach!

Regarding energy consumption, I have a time-of-use tariff so previously used the dishwasher’s delay-timer to schedule the dishwasher to run at night on the off-peak rate. However, since installing a rooftop solar PV system at the end of May, I have load-shifted to day-time. I now run the dishwasher from 10.30am when there’s sufficient solar generation to completely power the dishwasher, even during its peak consumption cycles, being: (a) 10 minutes from the start, when it heats the water; and (b) when it dries the dishes at the end of the cycle.

(In Melbourne, we’ve had a number of sunny days so far this winter, so there has been plenty of solar generation to cover heavy loads such as the dishwasher and steam iron. Admittedly, it is a large-ish PV system, sized at 5.76kW.)


#11

Anything containing Aluminium or Aluminium Alloy should not be washed in a dishwasher. The Alkaline compounds used in the detergent (whether powder or liquid) react quite strongly with the Aluminium and corrodes it, this also degrades the performance of the detergent causing it to not clean as effectively… Over time if Aluminium items are continually washed in the dishwasher they will become pitted and dull.


#12

No doubt about it @tndkemp. We do need a better performing dishwasher.

There was one installed when we moved in, & I won’t get rid of it while it works as that would be an awful waste. So till then, it’s handwashing.

PS I had the same experience at the previous abode.


#13

I use the cheapest DIshlex that Choice recommended - it has a knob and some lights but nothing fancy and cost me just south of $400. I’m a single dad and work full time, so I have lots of plates and cutlery and run the machine maybe twice a week, on pot-scrub cycle every time, loaded to the max and then some. I run it at night when it doesn’t use my solar (the company pays me more for solar than it costs me off-peak - go figure - I feel bad in a way, but only a little :wink: ). I think packing method accounts for a lot and I had some failures early on. Also recognising the stuff that needs ‘loosening’ - not often, but some of the baked on crud. I have no complaints - it does a wonderful job.


#14

Maybe only when the dishwasher dies.

There is a lot of dishwashing powder/tablets, electricity and water required (and also considering capital depreciation) to potentially recoup the cost of upgrading to a newer, more efficient machine. It could be possible that any upgrade would never have a payback…would only make you feel better thinking that you are actually doing something right for the environment (if one forgets about the waste created by throwing a perfectly good working old machine).


#15

As far as time savings goes the dishwasher wins in our house. We don’t bother pre rinsing, it all goes in during the day and put on last thing before going to bed. If we did dishes by hand we would use lots more water and detergent as we’d be doing them 2-3 times a day. I can’t stand dirty dishes piled up in the sink. Our dishwasher is basically used as a dirty dish cupboard throughout the day.
The other problem I have is when I wash dishes by hand I get water everywhere and then have to wash or wipe the floor and cupboards and sometimes change my shirt.


#16

I admit I like my bosch dishwasher, mostly for convenience, it goes on just before bedtime.
I don’t pay attention to manufacture claims much, I believe most are dubious. Prime example, how much printing can you get from an ink cartridge? You NEVER get what they claim.


#17

Thanks everyone for the detailed discussion, and please keep adding your experience to this thread. We recently had a look at dishwasher efficiency and found that the modern dishwasher is indeed very energy and time efficient. According to the ABS, we pour around 31L of water of water down the average household kitchen sink each day, whereas a dishwasher will typically only use 12-14L.

Some dishwashers also have ‘half load settings’ and timer functions to minimise power costs. There is also the measure of time spent, and the dishwasher gets the thumbs up here too. Of course as others have mentioned, it really can depnd on the items you are washing the size of the load and various techniques involved in an individual case by case business.

We have a range of articles and advice on dishwashers, be sure to check it out.


#18

I do find this surprising but we may be different to the norm. We have a Bosch dishwasher and invariably dish pan hands.

We wash up with about 5-6L of water after each meal. We find that when we use the dishwasher, we have to wash up after each evening meal anyway. We usually have timber or metal items that aren’t dishwasher safe. Likewise with items which have been in contact with raw egg or has cooked eggs on it…these aren’t remove in the dishwasher cycle.

In our household, we need to run the dishwasher at least one every 2 days otherwise we run out of cutlery or crockery.

When we use the dishwasher, we also rinse plates and bowls before stacking the dishwasher as the dishwasher tends to generate a smell…this can be hidden if we fully close the dishwasher door. But we also find that if we don’t rinse, the items on the bottom shelf tend to have food residues on them…I suspect this is from splash of the sump/bottom water back onto the items.

While the dishwasher in theory may use slightly less water, from my own observations is that based on how we use the dishwasher, it uses similar amount of water to hand washing…hence the dish pan hands.

We also have solar hot water which we manage so that we only use the booster occasionally each year (SHW has a consumption of about 30kW/year). The dishwasher as it heats its own water, uses significantly more electrcity in our household than using our solar hot water. Add the cost of detergents (dishwasher tablets/powder is more per month than dishwashing liquid detergent). There is no water or cost saving for us to use the dishwasher. Possibly the dishwasher is more time efficient, but not significantly in our household when one has to stack the dishwasher and than do a hand wash after the evening meal.

What I can say though, is the dishwasher is significantly better at removing tea and coffee stains from cups/mugs than hand washing.


#19

Oh lord, this does appeal to my lazy streak!!


#20

How convenient that would be, @mark_m! But not a very environmentally friendly process, unfortunately. :frowning: