This DIY solar oven project uses nothing but the sun’s energy to cook food. It is a slow cooker that is good for cooking soups, stews, rice, and bread. You can also use it as a food dehydrator. 

Here is how you can make a homemade solar oven out of a cardboard box and aluminum foil. If you find you like using a solar power oven, you can make or buy a studier and/or larger one. 

Before making your own portable solar oven, it is good to know a few general facts about them. 

A solar oven is a fairly simple device that harness then heat from the sun to cook food. Most solar oven cookers consist of an "oven box", reflectors, and a rack to put the food on.

Solar ovens work by capturing the sun’s light and concentrating solar power into a focused area to cook. The best solar ovens will also trap the heat via some sort of insulation.

There are several types of portable solar cookers. Easy solar oven projects (like this one) are panel cookers. The panel’s reflect the sunlight onto the cooking area. Cardboard solar oven plans (such as a shoebox solar oven) fall into this category. 

Parabolic mirror sun cookers use a curved mirror to focus the light. They cook faster but are harder to construct.

You can also get solar oven’s that have a backup electrical cooker system so if the weather is not good you can still cook. These are called hybrid solar cookers. 

When making a solar oven you will need the following solar cooker materials.

Place your pot in the cooler and cut the Styrofoam so it angles down while leaving enough room for your pot. Cut it from the inside edge.

Leave enough room for your pot

Cover the cut edges with tape to prevent the Styrofoam from fraying.

Line the inside with aluminum foil, shiny side out. Tape the aluminum foil down and fold it to size. Be careful you don’t tear it. Make sure you use tape and not glue so it is easier to replace it when the time comes. Paint the bottom black. 

Cut the heavy-duty clear plastic the same width as the opening of the cooler. Length-wise, you need to leave some going over the edge so you can pin it in place. If you’re using plexiglass, it needs to be the exact size of the opening. The weight will hold it in place.

Line the inside with aluminum foil, shiny side out

Make four reflectors from cardboard and line them with aluminum foil. See the image for the wing shape. The inside flap needs to be the exact width of the edge of the inside of the cooler.

Make four reflectors

Measure each wing separately since the diagonal lengths will be different. Making them wider angles means they will capture the sunlight for longer. Tape three of the wing corners together with duct tape.

Once the fourth panel is in place, you can use more tape to reinforce it. Leave one corner un-taped. You can hold it in place with a couple of holes and a twist tie, but that is optional.

Leave one corner un-taped

Put the rack inside your new solar cooking oven.

Here are a couple of different solar cooker designs using the same materials as the solar cooker project just explained. 

Several different solar cooker ideas

Preheat your DIY solar cooker by setting it out in the sun 30 minutes before putting the food in it. Put your food in it and let it cook.

The smaller the shadow, the more sun the solar cooking stove is getting. Turn it throughout the day to keep the shadow as small as you can. The wider the reflectors, the less you will need to move your homemade solar cooker.

Here are some estimated cooking times. Expect things to take longer on cloudy days.

Note: On a sunny day, this solar powered oven can get up to 150C (300F), so use oven mitts and sunglasses, and keep your pets and children away from it.

Now you know how to build a solar cooker. But you don’t have to follow these plans exactly. If you do not have access to a Styrofoam box, you can construct something similar with a cardboard box. Use these plans as a base to design your own solar oven ideas. 

As a side-note, a cardboard box solar oven is a good solar oven for kids to make. Maybe they can come up with the best solar oven design for a class project, have fun making a solar hot dog cooker when camping, or something similar.