Friday, May 24, 2013

Solar Box Oven

Solar Box Oven

A "solar oven" is something you can make for practically nothing, most likely from items you already have in your home.  You can use this method of cooking when the power is out or if you just don't want to have a hot oven on in the house in summer.  It's a good way to save money and use little energy, actually no energy other than the sun.  People in poverty stricken parts of the world are being taught how to use this method of cooking.

This worked fantastic! ...even better than I expected for my first attempt.  I had a hard time finding the right size boxes here in the house (and I'm 30 miles from town); and the top of the larger box was messed up, so I couldn't use the instructions I wanted.  I just worked with what I had and improvised, and it worked great!  

There are a lot of different instructions and ways to make solar ovens, but it really doesn't have to be complicated.

Here's the gist of it, with lots of photos below...

You need two large boxes with space between them so you can loosely stuff the sides in between with newspaper for insulation.

For the smaller box, paint the bottom a flat black color.  (I bought an inexpensive can at Wal-Mart, and it had the magic words "nontoxic when dry".)  Use regular Elmer's glue to glue aluminum foil on the sides of the inside the small box, shiny side out.  (...or some people use reflective windshield visors from the dollar store.  I bought a couple but went with the foil.)

Put the smaller box inside the larger box and loosely stuff newspaper in between the sides and under it if there is room.  Seal the top edges in between the boxes to hold in the heat by folding the flaps of the smaller box out over the bigger one and then cover the four corner holes that there will be with cardboard.  Attach a lid/flap on one side (or more than one side if you like) with aluminum foil on it to reflect more sun down in the box.

I had some ceramic tiles lying around, so I decided to paint them black and put them in the bottom as they retain heat.  I think they helped a lot, but you don't have to use those.  They also made channels under the pan so hot air could get under there.  You can use a rack for this.

You need to cover the opening with a piece of glass or clear hard plastic to hold the heat in, or you can put the food in cooking bags or a pot with a clear lid, etc.

(Oh, it's a good idea to get a meat thermometer to use as there is more guess work in the cooking times unless you just want to cut into it whatever you are cooking to check it.) 

Smaller box, bottom painted black.  
Then cover the inside sides with foil.

My smaller box was more shallow than the 
bigger one, so I put a couple cans in the bottom of the 
bigger one for extra support. 

 Stuff newspaper in the spaces in between the boxes and underneath.

Cover the open spaces around the two boxes to hold the heat in.
  (Fold the small box flaps out over the big box and cover the four corner holes 
that there will be.) All done except for a lid/flap with foil.

Attach a reflective lid to the side.  Ta da!  I painted some ceramic tiles I 
had and set them in the bottom also.

I used an old piece of window glass I had to cover it.  I used a stick to 
prop the lid where I wanted it.  Move it back and forth so that you can see 
where the light reflects to get it in the best position.  I put a chair behind it so the 
lid couldn't blow over too far.  You can see the sun 
reflecting down on the glass in the photo.  

I made my favorite biscuits, a mock Cheddar Bay Biscuit recipe. (If you are
 wondering about the rocks, my glass was a little too narrow on one side, so I put 
a strip of cardboard along the back and then put the rocks on top just to make sure 
to weight it down good since it had that extra piece under the back of the glass.)  

They were done in an hour.  (It was only around 52 degrees here today, and 
it was earlier in the day.  They would have cooked faster later in the day.)

Mmmm cheesy!

 All done with the butter and seasoning added over the top.  :)

I decided to put in a couple pieces of bacon.  :)


Update:  I got a new oven thermometer so was able to get accurate temperatures today.  I made Chicken Kiev (those get browned in a pan briefly before going in an oven).  It was around 70 degrees here today, and the temp in the box hovered just under 200; and the Chicken Kiev only took 2 hours to cook.  :)

I'll be cooking different things this summer and will post temps, cooking times, and photos. 

 A few links you can check out:

A simple one, "Minimum" Solar Box Cooker:  (click here)

A solar cooking web site with lots of info:  (click here)

"Easy Lid" oven:  (click here)

Mother Earth Living:  (click here)

Popular Mechanics:  (click here)

This web site shows a lot of different kinds of solar cooker designs.  (click here)

Update:  I cooked a Cornish hen...and it was yummy!  Some clouds were coming through, so I didn't get the best cook time possible.  It took 5-6 hours (75-80 degrees on this day), but I will do another one soon to get a more accurate cook time on a sunny day.  Still pretty cool when you can put a bird in a box outside and have a yummy tender dinner, using no energy and not heating up the house on a hot summer day.

This was during cooking.  The finished photo got deleted somehow. 
I'm going to do another update soon though.  :)  Oh, and 
I "butterflied" it so it would cook faster.  Just cut up 
through the back or along each side of the back and take it out.

Thanks for checking out my blog!  :)


  1. really good piece of information, I had come to know about your site from my friend shubodh, kolkatta,i have read atleast nine posts of yours by now, and let me tell you, your site gives the best and the most interesting information. This is just the kind of information that i had been looking for, i'm already your rss reader now and i would regularly watch out for the new posts, once again hats off to you! Thanks a lot once again, Regards, cornish hen recipe

  2. Concise and helpful nfo.
    Thanks! I enjoy your writing.

  3. Just wanted to say thank you so much! Between the pictures and written directions I felt brave enough to try. I really appreciate your blog.