Emergency Preparedness & Provident Living Newsletter
May 2025
Solar Cooking, Harvest the Energy of the Sun for nearly free!
By now most people know that you can cook delicious meals “off-grid” with only the power of sunlight. There are a few solar cookers that you can buy online that work very well. Some cookers are quite small and will only cook very small amounts at once like kebabs or eggs or cut up vegetables. The larger solar ovens are fantastic. I own one and love it! But if your budget is small or you want a fairly easy project to make with your youth group or family, you can MAKE your own solar cooker with a few easy to find items. You may already have some of these items in your home.
Think about your end goals. Do you want a fun family activity? Do you have a child that wants to make a cool science experiment? Do you want a way to cook in a situation when you are without power? Are there just two people to feed, or do you have a large family? Do you want to make a fast and cheap cooker, and you don't care if it falls apart after a couple uses? Or do you want to make a large cooker that will last a long time?
There are a wide variety of solar cooker tutorials on YouTube. I recommend watching several different video tutorials to see what things they all have in common, that make a cooker successful. And then find the tutorial that you want to copy.
Here are a few videos that I found to be very helpful when planning the solar oven that I made from boxes.
https://youtu.be/qYVm17uW3vY?si=dhKe0piBbY1ptfow Solar Box Oven Build and Test
https://youtu.be/DaiGiRqCTQw?si=SG5oNg-E_nB2uKIr How to build a solar cooker for cheap
https://youtu.be/J1sS9NtmKzo?si=ppgYGFBHvKaZicVk DIY Solar Cooker
https://youtu.be/f0pexxYQVVw?si=YY28q7JHG0u6HRYz The Best $35 Solar Sun Oven-Easy to make
These videos show you how to make an oven without a box;
https://youtu.be/cLCBQscnSdU?si=JQ4trrDZlCrBNJ4G Using a windshield sun shade
https://youtu.be/Hnynux2eGbY?si=Tfv4wlXDxQxv7Qgt Funnel solar oven
https://youtu.be/qfhgG6AcBiA?si=nyQ_9rHGhKSkJ9ci Building a cheap and easy solar oven
Things that most of these DIY Solar Ovens have in common are: Reflective materials on the sides of the inside of the box, reflective materials on the reflectors. Some models have 1 reflector, most have 3 or 4 reflectors. The more reflectors, the better. The bottom should be painted with a matte black paint. Black High Heat paint is best. Pans should be a dark metal for the best heat retention. And most ovens have a window.
I recently made a solar oven using 2 large boxes. I wanted to make a solar oven large enough to fit my 9x13 inch pans or a big soup pot. I have a large family, and I am used to cooking a lot of food at once.
I own a commercially made Solar Oven and it was a lot of money. My only complaint with that oven is that I can only use pans that are smaller than what I am used to. So I made sure that my homemade oven will hold my larger pans. And even though my homemade solar oven was a DIY project, I want it to look nice and last for several years. I am very happy with how it turned out. The following instructions and photos are from my project.
Box Style Solar Oven Materials
2 large cardboard boxes One box will fit inside the other. There needs to be a gap on each side and the bottom of about 1-2 inches for insulation that you will add.
Insulation materials of your choice, thick cardboard, shredded and compacted paper, packing peanuts, old fabric or clothes
Heavy duty tin foil or thin silver insulation that comes on a large roll, or mirrors
Silver Aluminum foil Duct tape that is sticky on one side. Used in HVAC construction
Matte black spray paint, High Heat paint is best
sharp scissors or a knife
Glue such as Elmers stick glue, glue gun, E600 etc.
Reynolds Oven bag, clear plastic, Glass or plexiglass for a lid and a way to cut these to fit
2 small handles or knobs to attach to the lid if using glass or Plexiglass
#1 Gather materials. Notes on the boxes; You can use square or rectangle boxes, it doesn't matter. Leave the box lid/flaps on the OUTSIDE box. These will become your reflectors. The 2nd box should fit inside the main box. You need a gap for insulation that will go on the bottom and up all the sides between the boxes. The inside box should be trimmed to be a little bit shorter than the outside box.
I was lucky enough to get a large, insulated box that was used for mailing groceries. It had dense 1 1/2 inch insulation around all 6 sides! The only insulation I removed was the insulation on top of the food. I took scissors and cut it off and saved it for another project. I found a second box that fit snuggly inside the insulation. That was a great find. You can always cut and retape a box to make it fit inside.
#2 Test fit your 2 boxes and the insulation with the largest pan you want to use in your oven. Make sure you are happy with the size of everything. Remove the inner box. Put your insulation material across the bottom. Put the inner box back in. Now fill all the gaps between the two boxes with insulation. Large gaps in insulation will allow heat to escape. Make sure you can close the lid flaps/reflectors flat with the inside box in place. Make adjustments as necessary.
#3 Line the 4 inside walls of the inner box with the heavy-duty aluminum foil. Overlap all seams. My seams were verticle. I used an Elmers glue stick for adhering the foil. Glue the foil to cover the entire inside of each box flap/ reflector. Use foil or the rolled insulation, to cut pieces that will cover the top edges of the insulation that is between the two boxes. Use foil and the silver duct tape to cover EVERY BIT of the cardboard boxes etc. The more reflection the better the oven will work. And as you cook, moisture will get trapped in the oven and that can ruin the boxes.
#4 Take the silver foil duct tape and measure out each piece needed before you cut it. Then carefully remove the backing to expose the sticky side. (this stuff will curl very easily). Place this tape all along every seam in the oven. I also applied it where the box flaps/ reflectors move like a hinge. Use this same tape along every edge of each reflector to hold the foil down. If you don't do this step, the foil will come off too easily.
#5 Measure the inside of the bottom on the inner box. Cut a piece of the rolled insulation or cardboard to fit in the bottom of the box. Test the fit. Once satisfied, take this new bottom piece and spray paint it a matte black. If you have a High Heat black paint, that is even better. Place the black bottom piece in the oven.
#6 Take your almost complete oven outside and spray paint the outside of the oven. You can paint the underside of the reflectors too. The dark color helps to absorb more heat. And it makes the oven look nicer too.
#7 Window: You can make a quick window with a cardboard frame and a Reynolds Oven roasting bag, heavy plastic or other material. I chose to buy a piece of 18x24 inch plexiglass at the hardware store. I bought the thinner of the two thicknesses. It is easy to cut and is a little bit flexible. My cost in 2025 was $18. I also had to buy a plexiglass cutter for $5 to trim it to fit.
Measure the inside of the oven at the top of the oven “chamber”. You want the window to sit on the top of the opening and to be easy to remove. My lid fits a little snug, but it is ok as long as I take my time removing the lid. Just make sure the lid does not leave an opening for heat to escape while the food is cooking.
Use E6000 or Super Glue to attach 2 small handles to the window. Allow the glue to dry overnight.
#8 Reflector Stabilizers: The slightest breeze may blow your reflectors closed. I bought a package of sticky back Velcro or Hook and loop fastener. I cut 4 pieces that are about 6-8 inches long. I then cut each hard piece of Velcro in half. Set the soft side pieces aside for now.
I hot glued the short pieces of the hard Velcro to the BACK SIDE of the reflectors at the right and left side. I then pressed one long strip of the soft side of the Velcro onto the pieces of the glued Velcro. It is the soft side that holds the flaps together. This also keeps the reflectors adjustable. See photo below. The soft pieces of Velcro can be removed and placed inside the oven when not in use.
#9 When ready to cook: Put a trivet or some metal canning rings on the bottom of your oven. Place your pan on the trivet. This allows hot air to circulate all around and under your pan.
Use dark colored metal pans if you have them. These will retain the heat the best. You may choose to buy a small, inexpensive oven thermometer to use inside your solar oven. I found some on Amazon.
The most important thing to consider when cooking with solar energy is the brightness of the sun. It can be cold, but it will work if the sun is bright. Keep this oven dry as it is made of cardboard.