Friday, February 09, 2007

Green Kitchen Tip #6

Dish Washing

Since beginning a re-model on our kitchen, I’ve had the opportunity to chose new, more energy efficient appliances. I actually got lucky on timing my purchases, because shortly after buying my new ones, the old ones began to fail. However, the one appliance I’ve held off on buying is a dishwasher.

Our kitchen came complete with ivory & black appliances from what I suspect was the 1980’s. Along with the giant side-by-side energy guzzling refrigerator, we inherited a standard electric range and a dishwasher that I refused to ever run. My rationale was that it consumed far more water and energy than I would ever use by handwashing two people’s dishes. Besides, I later justified, those detergents are more harmful than dish soap.

Times change, and now it actually costs more in energy and water, not to mention potentially productive hours, to get those dishes cleaned up by hand, than it does to use a modern dishwasher. Now I’m finding that the reasons to get a dishwasher are stacking up against me:

Scientists at the University of Bonn in Germany who studied the issue found that the dishwasher uses only half the energy, one-sixth of the water, and less soap than hand-washing an identical set of dirty dishes. Even the most sparing and careful washers could not beat the modern dishwasher. The study also found that dishwashers excelled in cleanliness over hand washing. (source)

Modern dishwashers heat water inside the machine, so heat is not dissipated on its journey through the piping from the home water heater, as it is in older machines.

But, all things considered, in order to minimize your impact on the environment, please follow these tips:

  • Wait until you have a full load to wash in the dishwasher
  • Don’t pre-rinse
  • Air dry
  • Use an environmentally friendly detergent, such as Seventh Generation.

Now is a great time to shop for a new dishwasher, because the Energy Star requirements for energy efficiency just became stricter, as of January 1, 2007.

If you chose to upgrade your dishwasher or other appliances, find a recycling facility in your area for your old appliances. Large household appliances are known as “white goods” – a relic from the old days when they were finished with white enamel.



At February 12, 2007 4:59 PM, Blogger Jeff said...

I'm always skeptical when I hear reports that don't include all the factors, and sometimes make claims that are hard to believe.

I don't own a dishwasher because it doesn't save that much time. The time difference between pre-rinsing and washing by hand is only minutes (all my dishes drip dry, so no time wasted there). So here comes the latest technology that says you don't have to pre-rinse. The skeptic in me says no dishwasher is going to remove the hardened shredded wheat crumbs on the bottom of cereal bowl. Hardened starchy veggies would be a close second.

Did the side-by-side test use a $.50 flow restrictor in the sinks faucet, cutting the amount of water used to hand wash by more than half?

What about on-demand hot water heaters, the kind that install in the wall right next to the device being used? These save energy in two ways. One, they don't keep a standing tank of water hot at all times, and two, heat loss from transfer is negligible.

Comparing a sink to a dishwasher, how much energy is used to manufacture and transport each? I don't know the answer to this so the sink may strangely use more energy, but it seems unlikely given the varied materials and number of parts in a dishwasher compared to a sink.

Lastly, if the drying element in the dishwasher is ever used, any energy savings from the last, oh, I don't know, 10 - 20 washings is lost. Heating elements are electricity hogs - big time.

I'm not denying the finding of this report; I just wonder how many factors were considered when conducting the research.

At February 14, 2007 1:54 PM, Blogger Jade said...

Ah, I've got to love a skeptic. Yes, I have my doubts as well. Including the raw materials for building the dishwasher . . . although I suppose they COULD be recycled. When I consider not pre-rinsing I worry about melted cheese, myself, especially if the dish in question has sat for several days, waiting to be included in a full load. And since several things need to hand-washed anyway (pots, pans, plastic containers) and the sink/counters need to be wiped down anyway, I begin to wonder too.

You bring up a good point about a flow restrictor on the faucet. I might have to look into that.

At February 18, 2007 4:56 PM, Blogger OMM said...

I have to ask, but what dishwasher do you have that doesn't require pre-rinsing? I'm totally not kidding. Everywhere we've lived, none have worked without pre-rinsing.

At February 21, 2007 2:45 PM, Blogger Jade said...

Hey, OMM, that would be the Manual brand of dishwasher (me), except I still pre-rinse. ;) No, I'm not speaking from experience, but from what I've read about the new generation of dishwashers. Anyone out there have any experience with them and with not pre-rinsing?


Post a Comment

<< Home