High Efficiency Microwave oven

khotton
khotton Solar Expert Posts: 38 ✭
in Energy Use & Conservation #1
I am curious if high-efficiency microwave ovens are available. I have "googled" the web and there are some mention of "energy star" in reference to microwave ovens but have found no particular model that actually states it is such. It seems the microwave oven that I own (based on name plate values of power input to maximum microwave cooking power is only about 70% efficient.

I guess I am just asking the "experts" on this forum what they know about high-efficiency microwave ovens.

Thanks, Kevin
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: High Efficiency Microwave oven

    I have not heard of high efficiency AC microwave ovens... But I have seen this article that claims the efficiency of a microwave oven is very dependent on voltage--which when used with an AC inverter on a battery bank, is very dependent on the voltage of the battery bank...

    This is a 17 year old article published in a now defunct magazine... So take the results with a grain of salt.

    But, if the test was properly done, it is possible that your inverter design (voltage regulation, sine wave vs mod-square wave) and battery bank voltage may have more effect on your microwave efficiency than the microwave oven itself.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: High Efficiency Microwave oven

    this is an aspect i hadn't thought of, but i'd suppose there'd be room to improve upon them. it would not amount to much as you are really just cooking with microwaves or simply put, small radiowaves. they could improve the draw from the clock circuit, but that draws very little. the problem with the clock's little draw is that it is all of the time so placing a switched power strip to turn it off and on would help greatly in the overall scheme of things.
    unfortunately, the high draw while cooking will always be there even if they do shave a few watts from them. on the positive side is that they cook in little time making the overall kwh small.
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  • backroad
    backroad Solar Expert Posts: 185 ✭✭
    #4
    Re: High Efficiency Microwave oven

    I've got to say that my large microwave sounds like it's struggling since we've moved on to solar power and it takes long to heat things. I've recently upgraded to new L16 batteries and an Outback 3524 inverter. I'm guessing that this is NOT normal?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: High Efficiency Microwave oven

    You may need to borrow a o'scope to check the voltage and current (see if peaks are flattened, power inverter wave forms, voltage issues).

    Perhaps getting a small auto-wound transformer or variact and adjust the voltage up 5-10% (assuming this is a cheap oven) and see if things change (monitoring with a good RMS volt meter).

    Lastly, it may also be brand dependent... Try a Samsung or Panasonic (borrow from friends?) and see if any better.

    :confused:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • System2
    System2 Posts: 6,290 admin
    #6
    Re: High Efficiency Microwave oven

    It's quite possible that virtually all microwave ovens would be considered Energy Star units, because of their much greater efficiency at heating or cooking smaller amounts of foods. Smaller, for example a turkey drumstick or two, verses a 30-pound turkey, which would be more efficiently cooked in a regular oven, even if you could cram it into a regular microwave.
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #7
    Re: High Efficiency Microwave oven

    Just curious -- don't know the answer -- what about the new Panasonic "Inverter" microwaves? I seem to recall claims of higher-efficiency power supplies...

    HTH,
    Jim / crewzer
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  • lamplight
    lamplight Solar Expert Posts: 368 ✭✭✭✭✭✭
    #8
    Re: High Efficiency Microwave oven

    wow never heard of those.. all i could find was this

    http://www.abtelectronics.com/images/products/PDF_Files/Panasonic-InverterTechnology.pdf

    its basically marketing not too technical. :cool:

    i have been thinking about a new microwave myself. we have a good sized range one i put in that uses about 1200w. i drink alot of coffee so i brew my pot in the am with an automatic shutoff right after brewing (cool feature on the maker), and i microwave cups all say long... i hate to think how much power my coffee habit uses up. so.... still these mic's look to use less power. encouraging, though id like more data... can you set them for 60% power as indicated? if so i might actually run one on my little 600w inverter if required!
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #9
    Re: High Efficiency Microwave oven

    Matt,

    I've just learned about these "inverter" micowave appliances, So I see I have a new research project ahead of me...:cry:

    The implication of 1300 W out from 1250 W in sounds a bit odd... I'm thinking about loading a bunch of 'em into the back seat of my pickup and seeing if I can improve its fuel economy...;)

    The literature suggests to me that lower power levels would reult in a reduced steady-state power requirement, rather than variable duty cycle pulses of full power...

    Interesting...

    Regards,
    Jim / crewzer
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  • lamplight
    lamplight Solar Expert Posts: 368 ✭✭✭✭✭✭
    #10
    Re: High Efficiency Microwave oven

    i think im going to get one of the small ones for my home office (1.2cf) as a test. i can get one for under $100, instead iof replacing the perfectly good over the range one a small additional one might make more $ sense. i think the numbers they refer too are not actual output (as youre right but thats pie in the sky) but maybe the equivalent heating wattage.. sort of like the comparisons they do w/incandescents vs CF (i could be wrong that was how i read it though.. simply put more efficient.

    too bad nobody has one yet to report on real worl power usage.
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  • System2
    System2 Posts: 6,290 admin
    #11
    Re: High Efficiency Microwave oven
    lamplight wrote: »
    wow never heard of those.. all i could find was this

    http://www.abtelectronics.com/images/products/PDF_Files/Panasonic-InverterTechnology.pdf

    ... can you set them for 60% power as indicated? if so i might actually run one on my little 600w inverter if required!
    Usually not. In almost all cases, the lower power levels are achieved by simply cycling the full power on and off, so you would still need an inverter capable of handling the full power. If you listen carefully while your microwave is running on reduced power, you can usually hear it cycling. Much like your home thermostat cycles your furnace on and off, to supply only the heat needed.
    I have however, seen a couple of microwave ovens years ago, that actually changed the high voltage curcuit capacitor value, using a combination of 2 HV capacitors, to give a constant lower output, but they only had 3 power levels.
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  • lamplight
    lamplight Solar Expert Posts: 368 ✭✭✭✭✭✭
    #12
    Re: High Efficiency Microwave oven

    Hi Wayne, checkout the wording in the article, they are talking about exactly what youre saying i think, it sounds like they do. i am going to have to find out ;)
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  • System2
    System2 Posts: 6,290 admin
    #13
    Re: High Efficiency Microwave oven

    Oh Yeah!! I just read their info and it does sound completely different! Sounds like technology has been marching on, while I stood still! LOL
    Wouldn't it be nice to have one checked with a "Kill-a-Watt" unit., or better still, actually tried on lower wattage, using a lower wattage inverter, just to be sure of exactly how they power that lower output. Hopefully it's not just full power being chopped up at high frequency, rather than for example 15 seconds on / 15 seconds off. But then again, even if that were the case, it MIGHT still work OK on a low power inverter.
    Interesting.
    Thanks
    Wayne
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #14
    Re: High Efficiency Microwave oven
    lamplight wrote: »
    wow never heard of those.. all i could find was this

    http://www.abtelectronics.com/images/products/PDF_Files/Panasonic-InverterTechnology.pdf

    its basically marketing not too technical. :cool:

    i have been thinking about a new microwave myself. we have a good sized range one i put in that uses about 1200w. i drink alot of coffee so i brew my pot in the am with an automatic shutoff right after brewing (cool feature on the maker), and i microwave cups all say long... i hate to think how much power my coffee habit uses up. so.... still these mic's look to use less power. encouraging, though id like more data... can you set them for 60% power as indicated? if so i might actually run one on my little 600w inverter if required!

    If you put your coffee in a pre-heated thermos/carafe (good one!) it will stay hot all day. We make ours the night before while the woodstove is hot and keep it over night. Hot coffee in the morning, no waiting, no reheating

    Just a thought.

    Icarus
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  • lamplight
    lamplight Solar Expert Posts: 368 ✭✭✭✭✭✭
    #15
    Re: High Efficiency Microwave oven

    Icarus

    yea, we had that exact conversation here some time back. i had the same idea : i actually bought and returned 2 separate thermal carafe models for various reasons. i just went back to my regular electric coffeemaker. finally someone here recommended a cuisinart thermal carafe maker as it really keeps it hot unlike the cheapo delonghi units i tried, although at this point i am frustrated so havent bought further and actually let the idea get old.. i suppose i would try another one if i knew it was saving me power (easy to measure throughout the day thats for sure). so, what model do you have that works so well for you?
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