From an environmental point of view, using a solar oven has got to be one of the most productive things you can do because you are not taking anything from the earth that isn't freely given, and no pollution is created in your endeavors.
Using a solar oven is also a great way of cooking if you are in a crisis situation, and there is no other way of cooking your dinner. You can cook the majority of things with a few exceptions, such as fried food, and produce that needs to get to a high temperature quickly. Apart from that, the only limitations are the ones you impose yourself!
There are a few different types of solar ovens but the basic principle is the same: they take solar energy - sunlight - and concentrate it into a heat source capable of cooking. A panel solar oven is made of reflective panels that surround a cooking pot that is usually placed in a plastic cooking bag that helps trap the heat. A curved solar oven, otherwise known as a parabolic concentrator, cooks at high temperatures by concentrating reflected light into the pot. These ovens need constant supervision because of the temperatures they reach.
A box solar oven is an insulated box, a glass door and a reflective panel; your food is cooked inside the box by the trapped heat. If you use the type of solar oven that cooks at moderate temperatures, you will discover another benefit: you can assemble your ingredients in the morning, leave it, and come home to a cooked meal, just like a slow cooker, without using any fuel that has to be paid for! There is no need to keep stirring, and the food won't burn. The size of a solar oven also means that it is portable so you can take it camping, or even on picnics. To make your own solar oven, first of all find two boxes - one will need to fit inside the other with a two to three-inch space on each side. Line the bottom of the larger box with crumpled newspaper, then sit the smaller box on top of this and stuff the space between the sides of the two boxes with more crumpled newspaper. Once this is done, line the inside of the smaller box with aluminum foil. Either fold the edges of the foil over the top of the box to hold it in place, or use non-toxic tape instead. Do not use duct tape or Styrofoam because they can give off toxic fumes when heated. The bottom of the box needs to be lined with black construction paper to absorb heat.
You are now ready to lay a piece of cardboard on top of the larger box and to trace the shape of the box onto the cardboard. Add another two inches to the trace line and cut out so you can make a reflector. Once this is done, cover the cardboard with aluminum foil making sure there are no wrinkles, and fixing it in place with non toxic glue or tape. You can now staple the reflector to the outside back of the larger box. Situate the solar oven with the box opening at the top and the reflector facing the sun so you gain maximum heat. It takes about 30 minutes for the oven to heat up, and cooking time is typically twice as long as using a conventional oven. Once the food is placed into your solar oven, stretch plastic wrap over the top of the larger box and secure with tape. This will keep the heat contained in the oven - all you have to now is relax and wait for your dinner.