infohound2006

What's with the Miele DW energy usage vs. Bosch's 180 kWh??

infohound2006
10 years ago

I was almost set to get a Miele Optima vs a Bosch 800 series, but then I got curious that the showroom touted the energy rating of the Bosch, but the Mieles had no tags. It took looking, but the Miele.ca site has good specs.

And now, I am aghast. How is it that the Bosch uses 40% less energy than the Miele Optima? Miele, whose slogan is "immer besser", "always better"?

- 297 kWh for the Miele Optima G2432SC

- 180 kWh for the Bosch 800 Plus Evolution (SHE68E05UC)

What would make the Miele such a comparative energy hog? I do hope there's a simple explanation that someone here knows.

Comments (24)

  • whirlpool_trainee
    10 years ago
    last modified: 5 years ago

    That's indeed "interesting". I've looked up the values on energystar.gov and they are exactly as you quoted. However, EnergyStar says the Miele uses 5.17 gal per cycle vs. 1.57 for the Bosch. Clearly, something is wrong here.

    My guess would be that Energy Star uses the Normal/Regular cycle to evaluate water and energy consumption. I once read that they'd run the dishwashers with clean dishes. My explanation would be that the Miele does not use its turbidity sensor on the Normal Wash, while the Bosch does. So running clean dishes through the Bosch will obviously cause it to drastically reduce water and energy consumption, while the Miele doesn't differentiate between soiled and clean dishes and always uses the same amount of water and energy (on Normal Wash). That's my guess.

    That being said, B/S/H (Bosch Siemens Home Appliances) does make extremely energy efficient appliances. More efficient than comparable Miele appliances.

    Alex

    Here is a link that might be useful: Siemens Ad

  • 59 Dodge
    10 years ago
    last modified: 5 years ago

    "And now, I am aghast. How is it that the Bosch uses 40% less energy than the Miele Optima? Miele, whose slogan is "immer besser", "always better"? "

    Yes but Note they didn't say "Better for who", in this case the electric company-----xtra income for the Utility Company(LOL)
    Now, before I get "Yelled at", I have a Miele Optima(3 years now), we like it, but since there are only 2 of us here, (No we are Not "Empty Nesters") We are "No Nesters",
    it is rarely used, most the time we hand wash the dishes, sooooo No additional income to Power Company.
    Good luck on "Your Choice"!!
    Would I recommend the Miele---Yep, when we do use it we luv that silverware tray up on top, and in fact that is the reason we bought it!

    Gary

  • mrtimewise
    10 years ago
    last modified: 5 years ago

    We have the SHE68E15UC. I think I'll take home a laboratory grade power analyzer from my office tonight, and actually measure the energy consumed by the Bosch during a normal load of dinner dishes. I will post that info here.

    The power analyzer I have is more accurate than any other analyzer made. They are used worldwide by appliance companies and any company needing to document laboratory measurements for Energy Star ratings.

  • aprince
    10 years ago
    last modified: 5 years ago

    The Miele is connected to the cold water supply, whereas the Bosch is connected to the hot water supply. Among other things, this deflates the KWH rating on Bosch. What this means is due to variable energy loss on a hot water line as oppossed to heating the water at its source, i.e. like a Miele, consumers can be deceived by ratings.

    This is just one example, of many, that makes Miele who they are.

  • leonardz
    10 years ago
    last modified: 5 years ago

    Well, this energy rating is largely why I wanted a BOSCH SHE68E15UC over the Miele Optima. That and the lower water usage.

    So : under the identical conditions, do we still see a Miele using more water and energy than the Bosch?If the huge difference is because of the hugely different measurement conditions, how does one compare an Optima to the Bosch?

    Has anyone actually used both for an extended period of time? I like the Miele baskets and layout more than the Bosch, but conservation is more important.

  • 59 Dodge
    10 years ago
    last modified: 5 years ago

    To leonardz: You seem to have a good handle on energy conservation. For folks with similar interests, could you elaborate on your other kitchen appliances as well as lighting for it, also tips on how to save on heating or cooling the kitchen (or the whole house)or any other inputs you might deem helpful. I think it's hard to beat the "Energy" one saves by hand washing the dishes, whevever possible---ya, I know it expends "Homo-Sapien" (Maybe mispelled)energy, but we don't get a utility bill for that (Yet)!!

    Gary

  • antss
    10 years ago
    last modified: 5 years ago

    "Clearly, something is wrong here. "

    Yes there is - there is no standard by which all measure by. Rather it is so loose as to no give an accurate comp head to head.

    Like Prince said, Bosch may not be accounting for the hot water in their test or the $$$ spent ot produce it. In almost all locales electric heating of water at the source is the most efficient and cheapest way to go. Also 40% (if even accurate ) of $20 a year isn't exactly going to break the bank is it?

    Gonna be rea interesting to see what leonard measures.

  • infohound2006
    Original Author
    10 years ago
    last modified: 5 years ago

    Prince's theory about hot vs. cold water intake makes a lot of sense, and is reassuring. Pity that the energy use tests aren't specific enough to account for such things, or to at least have a footnote to explain such a key factor.

    It's not that the extra $20 would break the bank (esp. since much of our electricity will come from solar), but the energy efficiency is an indication of the company's values, and the care with which it designs products. I expected these two companies' DWs to have made similarly good choices in the key items like heating element efficiency, pumps, and how effective the drying phase.
    If I'm going to be spending an extra $500 for a dishwasher, I want it to be the pack leader in reliability, efficiency, as well as ease of use.

    Mrtimewise, I'll be interested in your data on the Bosch's power consumption. Thanks! Please also let us know if your Bosch is connected to hot or cold water.

  • aprince
    10 years ago
    last modified: 5 years ago

    Not a theory. Saw it in both owners manuals with my own two eyes.

    "but the energy efficiency is an indication of the company's values, and the care with which it designs products."

    Your right, so compare the two comapanies.
    Miele manufactures all their parts, does their own service, therefore; if parts are replaced, they go back to where they were manufactured. This is an exceptional environmental philosophy. Also sold only in independents (professionals). Service can be cumbersome but is clearly the prototype for futureservice IMHO.


    Bosch, made in Germany or US, parts made all over the world, maybe China?. Service done by local Bosch servicer. Parts end up in back of service shop, thrown out 5 years later.
    Bosch, sold in any department store. Department store customers tend to look for deals. Deals lead to inexpensivwe, inexpensive leads to cheap, cheap leads to shortcuts, and short cuts lead to the dark side.

    Clearly they both make great dishwashers. However; one comapany is just like all the rest while the other clearly has no peer.

  • mrtimewise
    10 years ago
    last modified: 5 years ago

    I will post the energy consumption info with the set-up conditions.

    Unfortunately, we had an unscheduled visit to the vet's office for our Corgi last night so my tests were delayed. I'll post later tonight.

  • warmfridge
    10 years ago
    last modified: 5 years ago

    Very interesting discussion. I don't think the DW data are comparing apples to apples when it comes to the cost of heating the water. It would matter considerably if the DW was heating the water using electricity, vs an electric hot water heater, vs gas, oil, solar or some other energy source.

    My new Optima was hooked up to my hot water supply, which has 130+ degree water. The water is heated by my oil furnace, which seems like it runs almost constantly this time of year (22 below here this morning) so there's a constant supply of hot water, and the DW probably uses minimal electricity to heat water for the normal cycle.

    Here's an interesting site with a lot of information about DW's and energy use, with even more info in the links at the end of this article. Some people who think they're saving energy by washing dishes by hand probably aren't.

    Here is a link that might be useful: DW's and energy use

  • buckydent
    10 years ago
    last modified: 5 years ago

    According to the salesman at PC Richard, Bosch doesn't have a heated dry cycle. It uses the heat trapped by the stainless steel drum to dry the dishes as a conscious choice to be more environmentally correct. Miele actually heats to dry and thus uses much more energy (and can get even plastic dry).

  • mrtimewise
    10 years ago
    last modified: 5 years ago

    OK, here's a bunch of interesting information on the power consumed by the Bosch SHE68E15UC which we installed last October.

    The testing I did was rather arbitrary, but the measurement tool is accurate to 0.02%...it doesn't get better than that.

    The test was run in the Auto Wash mode with a normal load of dinner dishes for 4 people. The incoming water was from the hot water supply, and I ran the water for a few minutes so the supplied water was already warm in the pipes.

    Whenever the dishwasher is powered by simply connecting it to the AC power there is a constant draw of 520.52 milliwatts (11.729 milliamps at 121.46 Volts - I didn't make a note of the power factor). This is a constant current drain the dishwasher draws even when it is empty. Any dishwasher will do this in some regard due to the electronics inside.

    When the ON/OFF button is depressed, and the door is open, the power increases to about 4 watts. This value varies as the blinking display flashes on and off. When the door is closed, the power consumption increases due to the outside display becoming illuminated (probably somewhat offset by extinguishing the door control panel display which can no longer be seen).

    When the START button is depressed and the door still open, the power consumed is about 5.5 watts.

    Upon closing the door, the wash cycle starts. It was at this point that I began timing the cycle and started the power integration. It is the power integration in Kilowatt-Hours (KWH) which is used as a basis for determining the Energy Star rating you see on the big yellow tags on appliances. In the case of a dishwasher sold in the US, I believe the government specifies that the single wash KWH consumption is multiplied by 215 (the expected number of annual wash cycles in a home - I might have the wrong number here as I am stipulating this from memory).

    When the Bosch starts up it goes through a number of tests which end up adjusting the total wash time. The tests include a measurement of incoming water temperature. As a side note, I have noticed that when cold water is being supplied to the dishwasher when it starts (because the water in our copper hot water pipes has cooled), the calculated wash time increases by about 10 minutes. In the test I'm reporting on here, the water was already warm/hot, and the calculated wash time started out at 1 hour and 59 minutes (1:59).

    Now I've got 2 hours of data which would bore everyone here. So instead, I'll give a few observations and then some final data.

    During the initial running of the wash cycle, the power consumed is low...in the 10 - 30 watt range. The power being used is just from the pumps moving water around and draining the first rinse water. This continues for some 13 minutes. At the end of this time the integrated power is at about .009KWH.

    At about 13.5 minutes the power consumption increases to 1317.3 watts. The current is 11.285 amps (with a power factor of 0.990). At this time the integrated power is at .020KWH.

    During the next one hour and 45 minutes, the wash cycle continues in various washing/cleaning/draining modes. After 1 hour and 59 minutes, the wash cycle has finished and the "Clean" indicator on the display is showing.

    The total consumed power at this time was 1.0439 KWH. It is this number which you have all be looking for. Multiply this by 215 (I think) and we'll get the Energy Star rating for the set-up I ran...which is certainly not the same as the testing mode Bosch or any manufacturer would have run. Nevertheless, this indicates an annual power consumption of 225 KWH per year. This is not too much different from the 180 KWH quoted on the big yellow tag that came with the dishwasher. Their 180 KWH is likely computed by running tests in a combination of wash cycles.

    So I'm pleased with the results.

    But there is one more very interesting and important item to note. After the wash cycle finishes, and the "Clean" signal flashes on the outside display, the dishwasher continues to comsume about 4.5 watts. This is the power used to keep the display illuminated and the electronics operating. After another 2 hours of "not yet unloading" the dishes, the total power consumed has increased to 1.0539 KWH. That is, an additional 10 Watts-hours has been used during that 2 hour period because I didn't unload the dishes when the cycle was completed. So a warning...unload your dishwasher when the cycle completes rather than waiting overnight. And turn OFF the dishwasher to minimize the power consumption to the approximate 500 milliwatt (0.5 watt) idle power.

    And, by the way, if you use the delay start feature, the dishwasher also consumes about 4.5 watts for the display and electronics as the delay time counts down. So delaying the start for the "up to 24 hours" can waste upwards of 108 watt hours. Do this every wash for the government assumed 215 washes per year and you've wasted 23.3 KHW in a year...over a tenth of the overall energy your dishwasher would consume!

    (Caveat: I proof read this only once before posting, so please excuse my grammatical, spelling, and numerical errors.)

  • dadoes
    10 years ago
    last modified: 5 years ago

    Interesting. The high current draw at 13.5 mins is of course for water heating. Do you have any info on what are the target temps to which it typically heats the water?

    Not relevant to Bosch and Miele ... my DishDrawer uses 0.68 KWH (for one drawer running, not both) for the heaviest cycle, which heats the main wash to 150F and the final rinse to 163°F. That's 0.68 KWH *including* heating the water on a tap-cold fill (approx 70°F at the time I tested). Lighter cycles of course use accordingly less power. I typically run one drawer, I'd say every 3 days on average ... depends on the pattern of cooking, having leftovers, having frozen, or having take-out. Rarely both drawers together unless cooking for guests.

  • whirlpool_trainee
    10 years ago
    last modified: 5 years ago

    For what's it worth, here is the manual for the UK version of the Miele La Perla - with energy and water consumption data for every cycle. Note: this is just a guide line, as the cycles on the US models can be, and probably are, programmed differently.

    Bosch/Siemens does yet not sell its most water efficient dishwashers outside of Germany. These models only use 1.8 gal. and 0.97 kWh to wash 13 place settings on the ECO cycle (connected to cold water). Their most energy efficient dishwashers with "Zeolite Drying" use 0.86 kWh and 2.6 gal to clean 14 place settings on the ECO cycle.

    Alex

  • mrtimewise
    10 years ago
    last modified: 5 years ago

    The high current draw at 13.5 mins is of course for water heating. Do you have any info on what are the target temps to which it typically heats the water?

    Once the water heating begins, the current draw remains at about 11.5+ Amps (1350 Watts) throughout most of the Auto Wash cycle. I mention this to point out why it is necessary to have a separate 15 Amp circuit for a dishwasher.

    In the Bosch user manual there is a chart of the temperatures to which the water is heated for each type of cycle and options. The info there is rather complex, so I inserted a copy of that chart here. There is also info on the water usage.

    I should probably run my own KWH test using the ECO cycle (Bosch calls it an "EcoAction option") instead of the Auto Wash cycle. It would be interesting to see how much less energy is used. I'll report that single number here if I run the test.

  • whirlpool_trainee
    10 years ago
    last modified: 5 years ago

    Mrtimewise,

    A note on the ECO cycle. In Europe, each dishwasher is labeled using a standard scheme, which rates energy consumption, cleaning performance and drying performance on a scale from A to G. Each DW manufacturer has a cycle on their machines which they specify to be used for these performance tests. It's usually called something like ECO, Energy Save or the like. These cycles run for 2.5 hrs. or more but clean and dry very well, indeed. They have to deal with the and coffee stained cups, glasses with burnt-on milk, egg, ground meat and spinach, which have been dried onto the plates for two hours at 176°F. Consumer magazines also use this cycle to conduct their tests.

    Bottom line: your (American) EcoAction might not necessarily be the same as our (European) ECO cycle, which is really a frugal but looong high-performance cycle.

    BTW: I, too, have measured the energy consumption of our Siemens on several cycles and with all options. I might post the results some time later.

    Alex

  • aprince
    10 years ago
    last modified: 5 years ago

    Lots of info on this thread

    Buckydent said, "According to the salesman at PC Richard, Bosch doesn't have a heated dry cycle. It uses the heat trapped by the stainless steel drum to dry the dishes as a conscious choice to be more environmentally correct. Miele actually heats to dry and thus uses much more energy (and can get even plastic dry"

    On the contrary , Miele does not heat dry, it uses the heat trapped by the stainless steel drum to dry the dishes as a conscious choice to be more environmentally correct. this is know as condensation drying, not to be confused with me being condesending, which I may be

  • antss
    10 years ago
    last modified: 5 years ago

    "is an indication of the company's values,"

    so is marketing and quality of raw materials. Perhaps you should be questioning Bosch's motives?

    bucky - you're a bit misinformed. Miele doesn't use heated dry as most Americans know it. It uses the same system as Bosch, it uses a very hot final rinse to get that latent heat into the system or steel walls - just like Bosch. They are both about equal in drying plastics.

  • sshrivastava
    10 years ago
    last modified: 5 years ago

    According to the salesman at PC Richard, Bosch doesn't have a heated dry cycle. It uses the heat trapped by the stainless steel drum to dry the dishes as a conscious choice to be more environmentally correct. Miele actually heats to dry and thus uses much more energy (and can get even plastic dry).This is what happens when you listen to idiot salespeople who know nothing. Miele and Bosch dry almost identically, using residual heat in the tub to evaporate moisture.

  • antss
    10 years ago
    last modified: 5 years ago

    Should be noted for accuracy that one of Miele's models has a door opener that opens it during the drying cycle. Teh claim is that it drys plastics better.

    I am not convinced and have used both types , and exhausting the warm moist air into the room has some drawbacks.

    To my knowledge Bosch has no such feature.

  • whirlpool_trainee
    10 years ago
    last modified: 5 years ago

    As promised, here are the energy consumption values for our 2006 Siemens dishwasher. These were mostly done with a full load. The dishwasher is connected to cold water - approx. 68°F. It's a European model with a 2000 watts heater.

    Some notes:

    - On the Auto cycles, the pre-wash is always heated (unless, of course, it's omitted by the soil sensor).
    - The Half Load function shortens the cycle and probably also cuts on water usage.
    - varioSpeed uses more water, heat and pressure to clean dishes 50% faster. Basically, it a non-HE mode.
    - All cycles finished with a 158° sanitary rinse.

    Cycle -> energy use in kWh

    Auto Plus 149 167° + VarioSpeed -> 1,85
    Auto Wash 131 149°-> 1,68
    Auto Plus 149 167° + VarioSpeed + Half Load -> 1,68
    Auto Plus 149 167° ->1,60
    Auto Plus 149 167° ->1,56
    Auto Wash 131 149° + VarioSpeed -> 1,55
    Auto Plus 149 167° -> 1,43
    Auto Wash 149 167° -> 1,39
    Auto Wash 131 149° + VarioSpeed -> 1,30
    Auto Wash 131 149° -> 1,19
    Auto Wash 131 149° -> 1,17
    Auto Wash 131 149° -> 1,16
    Auto Wash 131 149° -> 1,05
    Auto Wash 131 149° -> 0,98
    Eco 122° -> 0,96
    Eco 122° -> 0,96
    Eco 122° + Half Load -> 0,94
    Eco 122° + Half Load -> 0,88

    Alex

  • mrtimewise
    10 years ago
    last modified: 5 years ago

    Excellent info, Alex.

    And thanks for the proper use of "energy consumption" when discussing power integration to determine kilowatt-hours.

    BTW...send me a private email if you'd like to know the instrument I used to make my measurements.

  • infohound2006
    Original Author
    10 years ago
    last modified: 5 years ago

    Thank you all who contributed to this informative and (almost 100%) civilized conversation! It was very helpful to me in making the DW decision.

    In case someone wonders, we went with the Miele Optima, to be installed later this week. I chose it partially based on how convenient I find Miele's dish racks & utensil drawers, but definitely influenced by all your comments on this thread.

    The discussion about energy consumption was very informative, including the detailed energy consumption measuremements, and how the total can be swayed by whether the DW was connected to warm vs. cold water, and the measured wash cycles, and even little things like the flashing light. For me, what was also key was aprince's comparison of the values embodied by the two manufacturers, in which Miele is sold & serviced through independents, and takes back its parts.

    Since we'll be getting hot water from geothermal heating, and electricity largely from PV panels, the small energy consumption difference itself isn't as crucial to us as what the efficiency, design, and manufacture decisions say about each company.
    (Still, it feels very odd to spend $2K installed for a dishwasher! That's almost as much as for our Samsung RFG298 [at 30% off]. Still, those are two of the three appliances I'll use every single day, so after quite a bit of soul-searching I decided to go with the Miele.

    Again, thanks to all. And, after we move in, assuming we can plug the DW into a Kill-A-Watt, I'll post the energy consumption for our real loads in the Miele Optima. (unless someone with better technology already posts their energy consumption numbers for a Miele).