Energy-Efficient Cooking

stoveI took the Sierra Club’s quiz on “green cooking” the other day and was rather confused by the results regarding the efficiency of gas vs. electric stoves vs. microwaves for heating water. I actually think they had mis-keyed the quiz the first time I saw it; either that or it somehow magically makes more sense today.

So the question: Which is the most energy-efficient way to cook food? The answer is rather long, and the whole thing may be derailed by remembering that cooking accounts for only about 4% of the average fuel usage in a home. It might not be worth the effort to quibble about the small differences in efficiency – especially if your windows are drafty, your attic uninsulated, and your fireplace sucking heat right out of your living room.

But for those who want the long answer, read on…For stovetops, the efficiency list goes thusly: [source and source and source]

  • Electric induction (very pricey; you’ve probably never seen one of these around)
  • Electric stoves with sealed ceramic cooktops (halogen, for preference)
  • Electric coil cooktops (the most common kind)
  • Microwave
  • Gas stove

However, if you’re only boiling one cup of water or heating one serving of food, the microwave shoots to the top of the list. (Who really *cooks* in a microwave, anyway?)

Microwaves and crock pots are also much more efficient than either a gas or electric oven. So that helps me answer the question, “If I’m going to stew something all day, should I put the Dutch oven in the oven, or boil it on the stove or crock pot?” but again…I’m not making brownies in the microwave.

Additional things to factor in:

  • You will never recoup your investment in a new stove, let alone new wiring or gas lines, with current prices of electricity and natural gas.
  • However, prices are going up.
  • Natural gas is a fairly clean-burning fuel; if your electricity comes from coal, a gas stove is cleaner.
  • If your electricity comes from natural gas (and much of it does), I wonder if these “efficiency” ratings actually take into account the fact that you burn 3 units of natural gas to get one unit of electricity, then get n% of that heat back out of the electricity to put into your food. On a gas stove, you just get y% of the heat out of 1 unit of gas to heat your food.
  • HOW you cook probably makes more of a difference than the type of range you use. Cover pots when you cook; bake more than one thing at a time in the oven; cook larger batches and microwave the leftovers.

I will also make a Colin Powell-esque distinction: the “correct” answer to the green cooking question is as above. But the right answer is, “neither of these are terribly green” when you compare to something like a solar oven.

I guess this doesn’t make my personal list of Big Things I Can Do To Save The Environment – it’s more in the small-to-medium stuff category. If I had $500 to spend, I wouldn’t replace a functional stove. I’d replace an old-but-functional fridge or freezer, or insulation, or a clothes-drying rack.

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8 Comments

  1. kate said,

    November 14, 2008 at 4:08 pm

    that’s one heck of a clothes-drying rack… ;)

    does the list go most to least efficient?

  2. Emily said,

    November 14, 2008 at 4:26 pm

    Kate – to the best of my ability to parse all this, yes, the list is most-to-least efficient. With the caveat about whether electricity can be truly efficient because of the inefficiencies of creating electricity in the first place.

  3. Suzie said,

    November 14, 2008 at 5:28 pm

    Speaking of Sierra Club and green cooking — Your very own green cooking article is front page of the latest local Sierra Club newsletter.

    We’re having a volunteer day tomorrow (Saturday Nov. 14) 2-5pm at the NEW Center Building, 1100 N. Main Street in Ann Arbor, to get them in the mail. Everyone is welcome! If you can fold paper or use a stapler, you can help.
    </Shameless plug

    Link to the newsletter online:
    http://michigan.sierraclub.org/huron/HVG2008Fall.pdf

  4. Suzie said,

    November 14, 2008 at 5:29 pm

    Um, Saturday is November 15. (What day is it today anyway?!?!)

  5. Moms Kitchen said,

    November 14, 2008 at 9:05 pm

    I looked at your sources because I have always understood gas is the most fuel effienct for cooking, and your sources agreee with me on that. Gas is the most fuel efficient over electric – is that what you are saying, or am I reading your list upside down?

  6. Emily said,

    November 15, 2008 at 3:54 pm

    MK – Where are you seeing that gas is more efficient? That’s what I’ve always “known” but Umbra says “Microwaves are generally less efficient than electric stoves but more efficient than gas stoves.” This suggests that electric stoves are the most efficient, which seems all wrong to me.

  7. November 17, 2008 at 7:13 am

    I’d be curious to know if they studied different patterns of cooking. For example, I know that an electric oven is not the best choice for reheating foods, but what if you do multiple things to take advantage of the oven’s heat? Maybe flash dry some herbs or toast nuts as the oven heats up, bake a couple of recipes back to back, and then use the remaining heat once the oven is off for reheating leftovers or drying something else? Since I save a lot of cooking for the weekend, I often try to think in this direction to maximize the oven’s energy as well as to shorten my own efforts. :-)

    But I still want a solar oven. ;-)

  8. Emily said,

    November 17, 2008 at 9:32 am

    Jennifer-

    I think your points are good ones, that the WAY you use your appliance ends up being much more important than the fuel it uses. That was my take-away from all this…

    E,


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