Okay, so Armageddon is here and the power has gone out…permanently. Your shiny glass-topped stove doesn’t work, neither does the oven, and you have to cook all those pizzas in the freezer before they spoil! What’re you gonna do?
That’s easy: whip out the tinfoil and a couple of cardboard boxes, and build yourself a solar oven! Alternatively, you could build an oven that uses sticks of scrap wood for fuel.
This morning a reader commenting on the Weather! post remarked that it’s very easy to construct a solar oven. So of course I had to check that out. A quick Google search brought up this amazing site. By golly, you can build a solar stove that looks like a nun’s headgear turned upside down. You can make one out of an old innertube. You can make a portable stove out of an umbrella. You can make them out of cardboard boxes. You can even use a pizza box. And if you really want to get fancy, you can hook your stove to a kind of battery-run equatorial mount so it will track the sun all day!
Would one of these contraptions save us cheapskates money? It might, if you have an electric stove. The stove and oven are big energy hogs, especially if you cook indoors all the time. My power bill was $57 last month, and I didn’t turn on the heater or an electric space heater once. I rarely leave the lights burning in unattended rooms, and I only do a couple of loads of laundry a week. My stovetop is gas, but the wall oven runs on electricity. So most of the power had to have been used by the oven, the refrigerator, and the computer. Let’s say four appliances consume the lion’s share of the power (this is just a guess!): $57 ÷ 4 = $14.25.
So. You could stand to save as much as $14 a month by cooking everything bakeable in a solar stove.
Green? Well, except for the mining, manufacture, and hauling of aluminum foil and the wood-pulping, manufacture, and distribution entailed in making cardboard boxes, I suppose it’s green. It would be that much less coal mined or oil drilled. I suppose. Though the energy to make those products has got to come from somewhere.
Hey! Every little bit helps! Eh?
So, what could you cook in such a device? A little cruising shows that cooking is plain and time-consuming. Apparently a solar oven is the (relatively) green equivalent of the slow cooker. Cooking times depend on the kind of cooker you’ve built and, of course, the weather. Roasting a single acorn squash will take you four to six hours. Chicken is said to take anywhere from one to three hours. A pan of lasagne takes three hours, but rice (we’re told) can be cooked in half an hour or so—after the water comes to a boil. One enthusiast cooks beans (all day long) and beer bread in his solar oven.
So if you have some food laying around, come Armageddon, you should be OK, assuming you’ve also laid in enough tinfoil.
Scrolling down at the site of our original discovery, we come across something called a rocket stove. This gadget, built of old cans, barrels, bricks or whatnot, is designed to burn small pieces of wood, such as twigs, scraps, or other small pieces of combustible material. These things can be fairly large—here’s one used to cure tobacco—and certainly could be designed, with care, into a nice backyard bread oven.
From what these authors say, apparently a rocket stove can generate some pretty intense heat. A solar oven? Maybe not so much.
On the other hand, given a 118-degree day a solar cooker might get up some pretty fair heat. It’s already in the 90s here. Maybe later this summer I’ll give one of these gadgets a try.
Has anybody built a solar oven or a rocket stove? How did it work for you?
Thanks for the link. I’ll have to check it out. I saw someone mention “solar stove” on another site but they didn’t expand on that so I’m glad to see you write about it! =)
I think a slow cooker uses about 15 cents/day of electricity. So I see no pressing need to construct a solar cooker, though the concept is appealing. Tightwad Gazette also has instructions if memory serves.
Yes, I’ve built a solar oven before, but I live in the shade of a hill that eats up the afternoon sun. Sometimes I could get a fair temperature while I was “preheating” the oven in the morning, but because I made it of cardboard and tin foil the wind would mess with it and I wouldn’t get the optimal angle. If I were going to do it right, I’d either shell out the $200 for the version with a gasketed door and self-leveling bottom, or I’d build one out of wood, thick glass, and non-breakable mirrors. The plus to something like this where you live is you load it in the morning and have a cooked dinner at night without raising the temp of your kitchen. So in calculating your savings, you would also have to count the A/C you DIDN’T use. That’s hard to figure.
Personally, I would try this because I love experimenting and would keep trying until I got it to work. I would like to try the pasteurizing: I believe it needs to be 180* for 30 minutes. I too read something about this not long ago and this article is inspirational. Thanks,FAM!
I didn’t build a solar oven, but last spring I bought a Global Sun Oven online. I bake all my bread and it has been a major help with the power bill. I have to factor in the heating up of the house and the amount of energy it takes to cool it back down. In the winter here in AZ, it’s nice to bake indoors. It’s in the summer that the outdoor oven is such a blessing. The homemade ones are cheaper, but they don’t get and stay as hot. I’ve done lots of bean dishes and rice and they don’t take nearly as long as the times listed. I have to watch pasta closely so it doesn’t over cook. Love it! A rocket stove is my next project. 🙂
@ Patty: Really!? How interesting… Here’s a nifty video showing the Global Sun Oven. They cost about $300 and can be had here. It looks like one of these things would be ideal for slow cooking, covered roasting, and certain veggies like corn on the cob, potatoes, and yams.
We’ve used a couple solar ovens–one a cheaper kind that used a roaster pan, and another more expensive oven. It is indeed like slow cooking, and it will come in handy if the power’s out for prolonged periods of time.
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