University of Florida

Solar Cooking

Ovens, microwaves, and toasters are indispensable tools in the kitchen. These appliances run off of electricity, which means that they use energy to cook and are vulnerable to power outages.

Simple no-cook recipes and solar ovens provide opportunities to enjoy home meals, whether the power is out or you just want to enjoy having a no electricity meal.

Solar ovens harness the sun’s heating energy to cook (imagine the inside of your car on a warm day). They range from professionally built large structures to homemade recycled boxes. Box cookers are well insulated and have reflecting, absorptive, and glazing surfaces to collect and intensify heat from the sun’s rays.

We give two examples of solar cookers you can build, but you can try experimenting with your own design.

Building a Box Solar Oven

Pizza Box Oven

Materials needed:

  • One pizza box
  • Newspapers
  • Black construction paper
  • Clear plastic wrap
  • Aluminum foil

Make sure the pizza box is assembled and closed. Trace a square on the outside of the lid of the box. There should be about an inch between the edges of the box and the square outline. Cut three sides of the square, leaving the hinge side uncut. Gently lift the cut portion and fold the uncut side to create a flap. Line the underside of the flap with aluminum foil, securing firmly with tape. You now have the reflector for your oven.

Line the inside of the pizza box with black construction paper. This will help to absorb the sun’s heat. Stuff the edges of the box with newspaper to create insulation.

With the flap open, line both the underside and top of the cut opening on the pizza box lid with plastic wrap. Once you have taped one side of the plastic, pull it tightly and then tape to secure. The plastic will let the sun’s light through, but keep its heat in the solar cooker.

Seal up any cracks in order to keep air from escaping (but make sure you can still open the box) and your new solar cooker is ready to use. If you want a larger cooker to accommodate bigger pots or dishes, try this construction with two cardboard boxes.

Two Box Cooker

Materials Needed:

  • Two cardboard boxes with lids (e.g. copy paper boxes, cardboard file boxes). One should be slightly smaller than the other
  • Insulation materials (e.g. rigid foam, fiberglass, newspaper, packing peanuts)
  • Corrugated cardboard
  • Aluminum foil or reflective material
  • Glass, Plexiglas, or clear plastic wrap
  • Black paint
  • Prop sticks
  • String

Paint the inside of the smaller box black so that it absorbs heat, and place the smaller box inside of the larger one. Fill the space between the two boxes with your insulation material.

Cut a hole in the box cover and cover it with plastic wrap or you can place glass or Plexiglas in the cut out portion. Cut a piece of corrugated cardboard to the same size as the box lid and cover it with foil to create the reflector for the cooker. Attach and hinge the reflector onto the cooking box. Attach props and string to hold up the reflector.

Using a Solar Oven

A solar oven can be used just like a crock pot or a normal oven. Solar cooker temperatures can easily reach between 200°F and 300°F, which means they safely cook dishes, even those containing meat, though cooking times will often be longer.

Remember that solar ovens require sunlight, so make sure you position your cooker in an appropriate place. Cooking times will vary with the amount and intensity of sunlight; the best time to use it is between 11:00 am and 3:00 pm.

Generally allow about double to cooking time than in a conventional oven, and use cooking thermometers to determine food temperatures.

Zucchini Quiche

  • 2 medium zucchini, chopped or shredded
  • ½ cup chopped onion
  • Diced mushrooms
  • 2 cups Swiss cheese, grated
  • 3 eggs
  • 1 cup biscuit or buttermilk pancake mix
  • ¼ cup oil
  • ¼ teaspoon Italian seasoning
  • ¼ teaspoon nutmeg
  • Salt and pepper to taste

Lightly oil a dark 9-inch round roaster. Beat eggs, stir in the biscuit mix and seasonings in the bottom of the pan. Add zucchini, onions, mushrooms, and cheese and stir lightly with a fork. Cover and bake in preheated solar oven for about 2 hours to until a knife inserted in the center comes out clean.

Pot Roast with Vegetables

  • 2 to 3 pound chuck roast (1 ½ to 2 inches thick)
  • 3 to 4 carrots, but in 3-inch lengths
  • 3 to 4 potatoes, cut in ½-inch lengths
  • 2 tablespoons water
  • 1 package dry onion soup mix

Place vegetables in bottom of dark pan and sprinkle with water. Put the meat on top and sprinkle with soup mix. Cover and bake three to four hours or longer.

Oatmeal Squares

  • 1 egg, beaten
  • ½ cup honey
  • ½ cup melted butter
  • 1 tsp vanilla
  • ½ cup whole wheat flour
  • ½ teaspoon baking soda
  • ½ teaspoon nutmeg
  • 1 cup rolled oats
  • ½ cup chopped walnuts

In a bowl, beat together egg, honey, butter, and vanilla. In another bowl, sift together flour, soda, and nutmeg. Add oats and walnuts to the flour mixture. Stir. Add the egg mixture to the dry ingredients. Mix well. Bake in a covered, greased 9x9 inch pan.

Other Recipes

With solar ovens you can enjoy stews, casseroles, roasted dishes, and baked desserts all by using the natural energy of the sun. Using solar ovens can be a fun and educational activity or a needed disaster time technique. Experiment with your favorite recipes.

Another way to decrease your cooking energy usage is to not use any heat at all. Fruit salads, vegetable and bean dips, pudding, dishes using canned tuna or chicken, are all different ideas for “no-cook” recipes. To view a list of recommended recipes, visit our page on no-cook recipes or view a more in depth list in the “Healthy Hurricane / Disaster Cookbook” (152KB pdf).

Adapted and excerpted from:

“Solar Cooking 101" (Material handouts, Presentation, St. John's County Extension, Oct 2, 2010).

Solar Activities for Students (SC125). Published by: NCSU North Carolina Solar Center (09/2001).

Solar Cooker

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