katakanadian (katakanadian) wrote in daily_granola,
katakanadian
katakanadian
daily_granola

Same old myth - now with debunkable numbers

I've always been suspicious of the claim that it is better to use a dishwasher than to do dishes by hand. Umbra Fisk's latest item repeats that claim and she gets a round of flack from several commenters including me (#7).

Note that my complaint is about the blanket promotion of dishwashers without any consideration of how hand washing can be more efficient. I am not trying to say that no one should use a dishwasher, just that it is misleading to promote it as a 'green' choice for home use.

I think that promoting dishwashers as green is a little like promoting paper plates as a water conservation plan. Yes, I've had people try to pull that one as an excuse for using paper at a party. If you are trying to save yourself some time and hassle then honestly state that but don't claim it's 'eco-friendly'.
  • Post a new comment

    Error

    Anonymous comments are disabled in this journal

    default userpic
  • 11 comments
It's like so many 'green' things: it depends on the user and the other technology in the home. My dishwasher uses 6.7 litres of water to wash all the dishes for a day for four people, and I don't use the dry cycle. I just turn it off and the residual heat dries them.

I've been handwashing lately using two sinks about half-full of water. I have a tankless hot water heater, so I have to run the water for about a minute before I get hot water, so about 2.5 litres goes to washing out the sinks with the cold water before I start filling them with the (finally) hot water. Between the wash and the rinse sink, I easily use another 5 litres, and sometimes if things are really mucky, I have to re-fill the wash basin, which means running the water until it's hot again. That's just once a day. My sister always hand-washes, and does them after every meal. But she has an older dishwasher and a solar water heater so it probably is more efficient to wash by hand, even doing them three times a day. And they don't rinse, so they save that way.

With my old tankless hot water heater, it only gave hot water if the tap was running full blast, so if I was washing pots or something that didn't really fit in the sink, I'd have to let the water run start to finish, or turn it off and then let it run until it got hot again.

It takes energy to heat the water either way, and if I'm washing by hand, I need the lights on and the music playing, so I'm using electricity too. *G* I run the dishwasher after we've gone to bed.

It's kind of like the bath vs. shower debate. You always hear that showers are better. Now that there are steam and multiple-head showers, that's not always true. A shallow bath uses less water than a long shower.

All that to say it's not necessarily shilling for the dishwasher industry, although we do have to look at what they say critically.
I like that you have thought it through as it pertains to your situation. I'm impressed that your dishwasher uses only 6.7L of water because the only numbers I have heard are 30L+.

Every time I have heard/read someone giving advice on hand vs machine dishwashing they have never talked about what kind of handwashing technique is so wasteful in order to help people judge for themselves. They just always say 'you'll be surprised to learn that machine washing uses less water than hand washing'. The implication seems to be that everyone should get a dishwasher.

Something that most people don't consider is the environmental cost of producing that machine. All the water and energy consumed and pollution produced during the mining, refining, manufacture, advertising, and shipment of said machine. It's still possible for the dishwasher to be more efficient/effective but the difference is much smaller than when you just compare daily usage.
True, true. The dreaded Life Cycle Costs will bite you every time. We have a terribly inefficent old fridge at the cabin (we won't even discuss the environmental impact of having a cabin. It's um, really old and has no running water?) but as we only use it a few weekends a year, the life cycle cost of replacing it would not really save anybody anything.

And the rain barrels I have in town were placed too close to the house and they overflowed in a major rainstorm and caused flooding and mold in my basement. I saved a little water but I used heaps of drywall and flooring instead. So my rainbarrels had a huge life cycle cost. *Sigh*

I work in Environmental Ed, so I try to do the stuff I'm asking other people to do, and it's interesting how it's not always as simple as all those green guides would have you believe.

I'm rambling. Sorry!
Ramble away!

It does require an awful lot of very broad thinking to assess what is really a better way to do things. There are so many caveats that it's easy to become discouraged or to start thinking we really have to go back to ultra lo-tech living. As I said to some friends earlier today, I'm about 80-90% sure that the human race has fucked itself because no one is willing to do what needs to be done (reduce population, give up cars, relocalize economies, restrict air travel, pay a fair price for everything, stop making crap trinkets, eat much less meat and fish, etc). I still have hope that there is 10-20% chance we will slow down climate chaos enough to maintain civilization.
Yeah, we're pretty hooped. When you see movies like Manufactured Landscapes or even Slumdog Millionaire and realize the extent of pollution in the developing world, and realize that they are developing, it makes my little reusable shopping bag look like a religious act rather than a real solution. But as a friend of mine reminds me, the fact that things have changed so rapidly over the past 100 years means things can change rapidly, and we may be able to change for the better as well. We have to keep finding ways of making it more mainstream and desirable to be more eco-friendly.
Every time I have heard/read someone giving advice on hand vs machine dishwashing they have never talked about what kind of handwashing technique is so wasteful in order to help people judge for themselves.

There's a great article on Treehuger that does exactly that. Their conclusion: "That is to say, it's possible to use less water and energy by hand washing your dishes, but it's not easy."

Something that most people don't consider is the environmental cost of producing that machine.

That's partly because in a lot of cases it is a sunk cost. My parents bought a house - it came with a dishwasher. I've rented half a dozen apartments over the years. At least half of them came with dishwashers. Given that the machines were already there it was pointless not to use them.
That's partly because in a lot of cases it is a sunk cost.
It seems we are pushed into so much waste that way. People are virtually forced into buying monster houses because nobody is selling anything sensible in the desired location. Smaller houses might actually cost more to build because you'd have to commission a custom job instead of getting a predesigned package.

As I said above, my complaint is not so much about whether someone chooses to use a dishwasher but with the promotion of them as always being better and encouraging people to buy more stuff unnecessary stuff.
Golly, after reading that article and the comments - people could save a lot of water if they could get hold of a plug for the sink, so they could wash dishes in it instead of having the tap running all the time to get water. Sink plugs are quite cheap and common over here :P
I am American but have lived in the UK/Ireland for years....in the States, if you're handwashing you run the water the whole time, and then rinse as you go. In the UK/Ireland, in my experience, you fill the sink and wash and put the dishes in the drainer or dry with a tea towel, without rinsing. The only water you've used is the sinkful. In my house, we boil one kettle of water to do the dishes, we don't even have a hot water heater.

When I mention this, the response is usually 'omg gross there will be dish soap on the dishes!!!'. But there isn't, not anymore than if you rinsed. And it's non toxic anyway, particularly if you use a natural brand. And if you use a dishwasher, you use rinse aid which is designed to stay on the dishes. And if you really can't get your head around it, run the kettle again and pour it over the dishes in the drainer. But washing dishes by hand is most definitely the greenest way to do it--you've just got to do it the green way. And it's easy.
Why boil water for rinsing? That's a big waste of energy. Any soap residue will rinse off quite well with cold water.

One of the most galling examples of energy and water waste I ever saw regarding dish washing was when a friend of mine washed out a 2L pitcher and then proceeded to fill it to the brim with hot water, dump it out, fill it to the brim again with hot water and dump it out again. This guy also habitually left ~100mL in his water bottles when throwing them into the burnable trash. >_<
Perhaps some dishwashers are better than others, but in my experience you have to handwash the dishes anyway because they always come out of the dishwasher with food stuck to them.