But is this just hype to sell crockpots?
I have been reading around and doing some analysis of my own, and I've decided that the hype is, well, only half true. It depends. But the information out there is somewhat lacking, so I've done my own calculations.
Wondering whether crock pots are really the efficient way to cook? Here is what I discovered:
I wanted to know what was applicable to my own kitchen. I know that cooking energy amounts to very little of most people's energy bill, and people get their energy from a zillion different places, so I haven't converted anything to prices.
I just want to see how much fuel is consumed.
According to my calculations, using a crockpot is a clear energy-saver if you use an electric stove and oven.
But here's the surprise! If you use a gas range, some dishes are actually more efficient to make on the stove-top!
(Note: If you are anti-numbers, anti-math, or anti-units that make you feel like you're in Physics class, just ignore the rest of the text and check out the chart.
Note #2: If you are super pro-math, and the electricity conversions from kWh to BTU don't seem right (like off by a factor of 3), please keep reading and see why I did it that way.)
If you want a little more of the process, feel free to continue. I got most of my data from "Mr. Electricity," who has a pretty great site devoted to saving energy in your home.
If you're using all electric appliances, the comparisons are very straightforward:
If you're cooking a roast, a typical crock pot on low for 8 hours will use about 0.8 kWh.
The typical electric oven at 350 for 1 1/2 hours will use about 3 kWh.
I'd use the crock pot.
If you're making soup, a typical crock pot on low for 8 hours will still use about 0.8 kWh.
The typical electric stove on medium heat for 1 hour will use about 0.8 kWh.
This one looks like a toss-up
But if you're making chili that has to simmer for hours anyway,
Same 0.8 kWh for the crock pot, but typical electric stove on medium for 4 hours will use more like 3.2 kWh.
The crock pot is the way to go for sure on this one.
But what if I cook with gas?
Then things get a little hairier. Gas appliances are rated in therms, not watts. So we can convert our kWhrs over to British Thermal Units or BTU to compare electric to gas. In addition, electricity is notoriously inefficient to produce from fossil fuels in power plants (like 33% efficient). So comparing BTU's side by side is only meaningful if we multiply our electricity BTU's by 3, to see how much actual fuel has been consumed. I assume the gas flowing through the pipes to your appliance is 100% efficient. Obviously, if your electric comes from solar, wind, or hydroelectric, this will not apply to you.
If I'm cooking a roast, the same average crock pot will use 2,730 BTU each hour, or about 29,000 BTU to finish the 8 hour job. The fossil fuel usage to make this much energy back at the old power plant is more like 87,000 BTU.
In contrast, the gas oven uses about 112,000 BTU at 350 for 1 hour, or 168,000 BTU for cooking a roast for 1 1/2 hours. Plus, if it has an electric ignition (which for almost all models, stays on for the whole cooking time...who knew?), it is drawing another 300W for 1 1/2 hours, or another 1,535 BTU (x3, to make 4605 BTU) .
This makes almost a whopping 173,000 BTU to cook a roast!
I think the slow cooker wins again!
Now, if I'm making soup: I'm still using 87,000 BTU worth of fuel back at the power plant to run my crockpot for 8 hours.
But the average gas range only uses 9,000 BTU on medium for 1 hour. Adding in my electric ignition (300 W for an hour, x3 for inefficiency), that makes a total of 12,071 BTU for an hour.
The stove top seems to be the clear winner here.
Even my slow-simmered chili, in the crock for 8 hours at 87,000 BTU, will simmer up on the gas range for only 48,282 BTU.
Now, just because I have a gas stove doesn't mean I'm giving up the crock pot. Even though it is less efficient for some applications, I still use my crock pot often, because:
- You can leave it on while you're out of the house or while you sleep.
- It makes even the toughest cuts of meat tender enough to fall apart on your fork.
- Long simmering times mean fantastic flavor!
- And my personal favorite, you can prepare dinner at 8 am when the kids are playing happily instead of at 4:30, when they've just woken up from their naps and are acting like hungry, post-hibernation bears.