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Community and Q&A

Effective Energy Star dishwasher choices?

LukeInClimateZone7 | Posted in Green Products and Materials on

Hello GBA community:
I often get questions involving dishwasher selections. Traditionally, my advice was, naturally, Energy Star. More recently, I’ve questioned this general advice given the user experiences that I’ve witnessed. The problem statement is thus: I’m seeing wasteful dishwashing practices in all of the homes that I’m involved with. The homeowners all have some brand of high-end, Energy Star rated dishwashers, and all of them pre-wash their dishes because the dishwasher just doesn’t do a sufficient job at washing dishes by itself.

The questions are these: Are dishwashers and associated detergents insufficient to the task of washing dishes these days? Are their specifics of water/detergent chemistry that would be result in improved performance with these dishwasher models? Are there specific features that I should look for in addition to Energy Star certification that would help improve model selection (e.g. installed grinder, cycle/rinse specifics)?

Here’s the longer background for those who wish to read further:

What I see is that all the dishwashers are used only as dish-sanitizers. The homes’ occupants all pre-wash their dishes, usually with sinks full of hot water and soap (at least 10 gallons of 110 degree water). Then they place the pre-washed dishes in the dishwasher for final cleansing.

I inquire about this and recommend that they should simply scrape off the food from their plates and place the dish into the dishwasher. They all invariably state that following this approach results in unclean dishes.

My Own Study:
In that moment with my clients, I received this information politely, but remained secretly incredulous. Since I don’t have a dishwasher, I had to use my own mother’s dishwashing habits during some holiday visit to study this problem.
I scraped some plates from a holiday dinner, placed them carefully in the dishwasher (a highly-rated brand in terms of performance and efficiency according to Consumer Reports). And, the dishes came out with a soggy crust of particlized food along with a bigger chunks that I didn’t quite scrape off.
So I cleaned out all the drain basin and spray nozzles (mostly clean), and tried again, this time on the heavy cycle, and while the dishes were slightly cleaner, they still had to be hand rinsed again to wash off a few bits of crud.

Granted– this personal study represents one data point (which is by definition not a trend). But, I’ve heard similar reflections from my clients’ experiences.

Other possible factors:
Detergents are all over the place– usually the standard supermarket brands (not especially ‘green’ detergents).
Water quality: Between Hetch Hetchy (pretty soft water) and Colorado River (almost too salty for irrigation), we got a range of water chemistries, and this problem seems to be consistent across those categories.

Literature Review:
Some literature review that’s available on this very site:
Alex Wilson had a nice article about dishwashers a couple of years ago:
My clients (and mother) who try to follow this advice result in unclean dishes.

And, Martin and Robert Riversong provided some interesting points and counterpoints (and poem!!) in this article

Robert properly points out that handwashing *can be more efficient than using a dishwasher. I completely agree, but unfortunately, that’s a non-starter for my clients.

Pardon my prolixity in this question, but any thoughts on this from the community?

–Luke Morton

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  1. GBA Editor
    Martin Holladay | | #1

    Start with Consumer Reports. Their testing shows that dishwashers aren't to blame: "Most of the 53 dishwashers in this report did at least a very good washing job in our tests even as federal efficiency standards have become stricter. ... We put each dishwasher through a tough challenge, using a heavily soiled 113-piece load to test cleaning prowess. Models that are able to handle that messy melange should shine on your less-demanding loads."

    More details are available in this Boston Globe article: "But Consumer Reports’ tests of 77 dishwasher models show that doesn’t mean you have to live with dirty dishes or ridiculously long cycles. Better yet, some of the biggest energy misers are also well priced. Bosch’s new Ascenta SHX3AR7[5]UC, $700, and Kenmore’s new 1328[3], $650, are among nine recommended models priced under $1,000. With a cycle time of 95 minutes, the Bosch was fastest in Consumer Reports’ tests after the noisier and less-capable Electrolux IQ EIDW5905J[S]. It’s also almost twice as fast as the new GE Monogram ZBD9900R[ii], which took three hours. Testers slathered plates with egg yolks, peanut butter, raspberry jam, and other stubborn goo to see which made the clean-plate club."

    Your choice of detergent matters. Check out this article: "When it comes to dishwasher detergents ... Finish Powerball Tabs and Cascade Complete All-In-1 ActionPacs earned the highest marks in Consumer Reports' ratings of nonphosphate gels, liquids, packs, pods, powders and tablets."

  2. LukeInClimateZone7 | | #2

    As always, thanks for your insight--
    I didn't state this in the question, but all the dishwashers selected were chosen after reviewing the Consumer Reports articles. They were all well reviewed in terms of their dishwashing performance. That still appears to be insufficient for these users in a way that I'm still trying to understand.
    And, I know for my aunt's dishwasher, she's a Consumer Reports obsessive, and the top selections, along with her very well rated dishwasher, still result in enough spotty dishes that she pre-washes by default.

    Perhaps what I'm asking for is any specific experience from among the community: for those who have experienced similar results initially, what methods, settings, and/or features that they have found work to ameliorate these results, and finally make people comfortable with minimal dish pre-washing.

  3. GBA Editor
    Martin Holladay | | #3

    I've never had a dishwasher, so I have no direct experience that might help your aunt.

    However, it seems to me that if I had a $700 appliance that didn't work, and if I ended up having to wash the dishes by hand anyway -- I might just disconnect the dishwasher and stick with hand washing.

  4. LukeInClimateZone7 | | #4

    My sentiments exactly! Hers is probably more of the $1500 dishwasher, but that just makes your point all the more puissant. In fact, I have an ongoing list of appliances and technologies that create the problem that they're exactly supposed to solve. hmmm, my friends say: "A problem in solutions clothing." (Is there a more inkhorn term that already captures this notion?)

    Back to dishwashers-- my mother has already resorted to washing dishes by hand, leaving her nice dishwasher to provide needed shelter for lost objects and dust bunnies.

  5. nelsonl | | #5

    Here's my experience. In my house we use a dishwahser regularly. I scrape off any food but I do not pre-rinse dishes. I have a dishwasher that was top rated by Consumer Reports three years ago (a Bosch). We use Cascade Complete tabs dishwasher detergent. We do not have hard water and we do not have a water softener.
    Our dishes come out perfectly clean.

    However, that wasn't always the case with previous older dishwashers and detergents. Plus we've even had previous detergents that have caused serious surface dullness/etching on glassware over time. One downside of the Bosch dishwashers is that they require periodic cleaning of their internal filters.

  6. knownothing | | #6

    We have a late model Kenmore (Whirlpool based) and use the Costco brand detergent that is rated very poor by CR. Dishes almost always come out clean even though we just scrap them before placing them in the dishwasher.

    Have you verified the dishwashers are hooked up to the hot water? I imagine you would get very poor performance if you used cold water.

  7. JoeW519 | | #7


    what you say was very true -- in fact understated -- for the dishwasher we had when we lived in an apartment. The dishwasher was probably installed when the building was first opened (1992) and probably has never been serviced. As Martin and you suggested, I simply washed the dishes by handm mostly because I did a better job.

    HOWEVER -- two months ago we moved into a house that was built in 2003. It has a Kenmore Energy Star dishwasher and works without fault. I've tried all the cycles and the really fierce ones (sanitize, pots/pans, etc) are really overkill. I use "normal" when things are pretty bad but, for daily use, limit the dw to the "Water Miser" setting.

    We use the "air dry" cycle of course and 120 degree water (at the water heater). We get our water from the same city as we had in the apartment, use the cheapest crap that Sam's Club sells, and do add "Rinse Away" through a little tank that stores it ... the dishes are clean and spotless (i.e., probably the Rinse Away), unless:

    -- I use the Water Miser setting on dried egg yolk, baked on grease, etc. Such matters are handled much better in the "normal" setting.

    -- I put greasy or coated pans on the top shelf. They need the pressure of the bottom cycle.

    If you['re wondering, the "Normal" cycle is 90 minutes; the Water Miser is 45.

    All I can think of re: the experiences you've had is what you suggest -- that there is a maintenance issue with the dishwashers, or that the water is different in some relevant way as we move from one region to another.

    Thinking out loud of variables -- would water pressure effect the performance?

  8. LukeInClimateZone7 | | #8

    Thanks for the testimonials. It's actually going to be helpful in encouraging my clients to engage in water/energy efficient dishwashing practices. Like most, my clients are social beings, and the personal testimonials as well as advice from (ahem) the nation's best (tm) greenbuilding advisor forum might be enough to make them wonder how, not if, they can get an actual dishwasher out of their dishwasher.

    I recently discovered over the holiday that two installations in my family have either cold water hooked up to the dishwasher, or a 30 foot long exterior hot water pipe that is only partially insulated.
    So, hot water availability may the issue with at least these installs. Secondly, I believe drain cleaning is also an important factor.

    Again-- many thanks for the advice.

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