Solar Cooking

In Kenya

On a sunny day, it can cook an entire meal for the whole family. 




Compiled and written by Michi Vojta, United States Peace Corps Volunteer (US PCV).

Major contributions from Barbara Ross, US PCV; Institute of Cultural Affairs; Solar Cookers International; Solar Box Cookers Northwest; and Gruppe ULOG. Graphics taken or adapted from Solar Cookers International and Gruppe ULOG.

Assisted by Prabha Prabhakar Bhardwaj, Women In Development Environment Network (WIDEN), Kenya for layout and Desk Top Publishing.


There are no limitations by patent laws for the reconstruction of solar cookers. Reproduction of information is encouraged as long as the source is acknowledged and a copy is sent to the author care of Peace Corps / Kenya, PO Box 30518, Nairobi, Kenya, East Africa.

Introduction to Solar Cooking

A solar cooker changes sunlight into heat and cooks food. It uses no fuel except the sun's energy--no wood, charcoal, gas, kerosene, paraffin, or electricity. The cooker works on three basic principles of physics:

  1. sunlight is absorbed by dark objects and converted to heat;
  2. shiny surfaces reflect and don't absorb energy;
  3. light goes through transparent materials, while heat mostly doesn't.

Therefore, the cooker is basically an insulated box that traps sunlight to cook. The adjustable reflector increases the solar radiation through the glass (or polythene) panes. The black matte floor and pots of the cooker converts the radiation into heat, which does not pass through the panes, remaining inside the cooker and cooking the food.

Some advantages of the solar cooker are:

However the cooker does need sunlight to cook, so it cannot work indoors or at night. Also it does not work as well in the early morning, evening, or on cloudy days. It cooks slower than traditional stoves (three stone, ceramic clay-lined jiko) and cannot be used for deep frying, because heat escapes when the cooker is opened.

Important Tips

The outside temperature of the air does not greatly affect cooking, as long as the cooker is properly insulated. This is mostly true for the wooden cookers, as the cardboard cookers are already less efficient.

The bigger the cooker, the higher the temperatures. However, the larger cooker will take longer the hear up, as it has more air space.

If building a cooker, especially if using polythene / plastic for the window, use two separate layers to create still air space in-between, which will conserve heat better than one layer. The glass panes in the wooden cookers are usually about 3 cm apart (1 inch). If using polythene, be sure the material is taut enough and will not sag and cling together.

Clean the glass/polythene window each time you cook.  Any dirt reduces the amount of incoming sunlight, thereby decreasing the cooking efficiency.

Place the cooker in full sunlight. Again, the more light, the better it cooks.

Put the cooker out while you are preparing the food. The cooker will preheat, reaching the necessary temperatures sooner and cooking the food faster.

Have the food in the cooker before 10 am, preferably before 9. The best cooking hours are from 11 am to 1:30 pm, so start early.

Use less water and salt. Because the water and nutrients are preserved, so is the food's taste.

Cut the food into small pieces. Larger portions take longer to cook.

Use pots with lids and painted matte (emulsion, not glossy) black on the outside and top. Most normal cooking dishes are appropriate, and the dull color absorbs light and converts it to heat quickly. If no lid is used, a black cloth can be used. In addition, a cloth can absorb the moisture condensing on the glass, which hinders cooking. One exception: baking cookies and other foods.

Use large, flat cooking pots.  Food gets cooked faster in a large, light pot filled one-third full than the same amount of food in a small pot filled completely. plastic containers may melt of emit fumes, while clay vessels or other thick pots will take longer to heat.

Place small wooden blocks under the pots. This will lift the pots higher in the box, where the heat is (heat rises). Also, this will allow the warm air to circulate underneath the pot, heating the food from all sides. however, the space between the highest lid and the glass panes must be at least 2 cm to prevent breaking the glass.

Close the lid tightly.  Any heat escaping will also increase the cooking time.

Adjust the reflector so that the maximum amount of light enters the cooker.

If you leave for several hours during the day, position the cooker so that it will receive maximum exposure during the key hours--from 11 am to 1:30 pm, when the sun's rays are most direct.

Do not open the cooker once it begins cooking if you can avoid it. Any time the glass lid is opened, heat escapes and the temperature drops in the cooker. When baking items with yeast of baking powder, the cooker should not be opened at all, as the dough will fall.

Use pot holders to remove the pots. They get very hot.

Food left in the cooker will stay warm for several hours. This can be prolonged by adding flat, clay tiles in the bottom while cooking, closing the lid after cooking, adding pillows into the cooker to retain heat (similar to a haybox / fireless cooker) or even covering the cooker with a blanket when the food is ready. However, food left overnight in the cooker or at room temperature (after the cooker has cooled) can spoil.

Purchasing A Solar Cooker

Solar Cookers International (SCI) has demonstration models, made of aluminum-lined cardboard, that are collapsible for “easy transport”-- assuming you don’t travel on Kenyan dirt roads via mountain bike or matatu. Also they are extraordinarily expensive for cardboard, especially on a Peace Corps budget. However, Children's Earth Fund will donate SCI's cookers to people on the condition that it be used to demonstrate solar cooking to school children within three weeks of arrival and the new solar cooking chefs (the students) report their results.

In addition, SCI sells WAPIs, or Water Pasteurization Indicators. These handy devices contain a wax which melts at 69 degrees Celsius (158 degrees Fahrenheit)--just above the temperature at which water is pasteurized. Once the wax melts and runs to the bottom, the water is safe to drink. WAPIs are inexpensive and can be purchased direct from SCI.

Clevelab in Littleton, Colorado, offers Sunspot, a mini-cooker. Again, it is a bit expensive and shipping is outrageous, but it works wonderfully well for children and demonstrations.  Mini-models can be easily constructed from cardboard.

From experience, wooden solar cookers are generally less expensive to purchase than to build, unless your site is extraordinarily remote. If you travel by train, the cooker can usually be put into the cabin for no extra charge. The construction is time-consuming and the cost of individual parts expensive.  Nonetheless, the plans for the cookers have been included.

Wooden solar cookers can be purchased here in Kenya. TransWorld Radio (TWR) builds cookers at their workshop in Nairobi on Ngong Road (near Ngong Hills Hotel). The design is basic and the cookers are mass-produced to keep prices low--they sell the cookers “at cost.” Institute of Cultural Affairs (ICA), just off Ngong Road, sells cookers that are made at the Kabiro Polytechnic in Kawangware. These are a bit larger, sturdier, and consequently more expensive.  Also ICA offers courses designed to teach local artisans to build cookers and local women to use and disseminate information on them. These two offices are a ten minute walk apart. Both addresses are included at the end of this booklet.

Verein zur Foerderung kleintechnologischer Nutzung von Sonnenenergie or VKSE (roughly, Association for the Promotion of Small-Scale Use of Solar Energy), associated with ULOG, sends assistants throughout the Third World "when invited" to teach solar technology provides financial support for solar projects.

Building Your Own Solar Cooker

Cardboard panel cooker

This CooKit is designed by SCI and is presently used in the Kakuma refugee camp in Northern Kenya.  It or a similar type of cooker has been used successfully throughout the world, from France to the United States, from Nepal to Kenya, with minor modifications according to latitude.  The difficulty is in getting the plastic bags for cooking. However, if they are available, this may be a cheaper and more convenient cooker—easier to make, transport, and replace.

From cardboard

Items needed to build a cooker with outside dimensions of approximately 66cm x 54cm x 45cm:

 Score each wall of the box with two lines, one 20 cm from the bottom (Line 1), another 25 (Line 2). If the walls are taller than 45 cm, score them at 45 cm as well (Line 3).

At each corner, cut from the top to Line 1 to create four flaps (see Diagram 1).

mabati in the bottom of the jiko to increase absorption.

The lid:

There are other methods for construction. Some of the more popular are included, though they are by no means the only ones.

From wood

These plans are modified from the ULOG model type from Switzerland. This standard sized cooker will have outside dimensions of 67 cm x 67 cm x 50 cm, a maximum height of cooking pots of 19 cm, and a capacity of up to 6 people. Plans for a family size cooker are also included in the pamphlet that can be obtained directly from ULOG; the address is included at the end of this booklet.  Lack of precision during construction will reduce the efficiency of the cooker. Work slowly and be careful when building.

Items needed to build a standard-size cooker (numbered as shown in the diagram, with measurements in centimeters):

  1. 2 glass panes--50 x 50 x 0.3
  2. 4 frames for glass, wood--54.9 x 6 x 2.2
  3. 8 retaining fillets, wood--49.5 x 1.4 x 1
  4. spacer fillets, wood--49.5 x 2.4 x 1
  5. 1 reflector lid, plywood--55 x 55 x .5
  6. 1 reflector foil, 55 x 55 x 0.1
  7. 2 galvanized steel hinges
  8. 1 wood prop for reflector--50 x 1.5 x 1.5
  9. nylon cord--100
  10. 1 cord tightener--3.5 x 1.5 x 0.5
  11. 2 hardwood window holding ledges--25 x 2.5 x 1
  12. 2 hardwood buffer blocks--5 x 2 x 2
  13. 2 wood revetments---67.5 x 6.3 x 1.5
  14. 2 wood revetments--55 x 6.3 x 1.5
  15. 3 steel chromium plated handles--16.5
  16. 1 aluminum stove bottom (trough)--86 x 86 x 0.3
  17. 2 wood frames for stove bottom--50.5 x 8 x 2.2
  18. 2 wood frames stove bottom--66.5 x 8 x 2.2
  19. 4 plywood frame joints--15 x 7.5 x .8
  20. 4 plywood side walls--67 x 27 x 0.5
  21. 4 wood legs--10 x 4 x 4
  22. 2 wood reinforcing strips--58.5 x 2.5 x 1.5
  23. 1 plywood floor--67.5 x 67.5 x 0.5
  24. 30 steel wood screws, countersunk--0.3 x 2 c
  25. 24 steel wood screws, countersunk--0.3 x 2.5
  26. 4 steel wood screws, countersunk--0.3 x 3.5
  27. 12 steel wood screws, countersunk--0.35 x 3.5
  28. 4 aluminum button head rivets--0.3 x 1
  29. 131 steel nails, flat-headed--0.14 x 2
  30. 18 steel nails, sunk-headed--0.14 x 3
  31. 14 steel nails, sunk-headed--0.14 x 5
  32. wood glue
  33. black, matte paint
  34. insulation material
  35. weather protection (linseed oil, varnish, etc.)


Dovetail ("tenon") or otherwise modify the 4 glass frames (2) so that they will fit tightly, as suggested in Diagram 6. Put the four parts together into a perfect (right-angled) square. Secure all 12 tenons with a nail (31) each.

Fix four retaining fillets (3) on the inner side of the glass frame exactly parallel to the outer edge and without spaces in the corners. Use three screws (25) for each fillet but no glue, so that they can be removed easily in order to replace a broken pane later on. The fillets should be bored beforehand (3 mm). Put one glass pane (1) in. This is fastened with four spacer fillets (4). You need three nails (29) for each fillet.  Before putting in the second glass pane, both must be cleaned thoroughly. To avoid condensation when the solar oven is used, treat the inner surface of the glass panes with either clarifying cloth or transparent soap.  The glass pane that must be protected is coated several times diagonally with the soap. Then you rub the soap lines with a dry cloth until the glass is clear again. The four remaining fillets (3) are used to fasten the second glass pane parallel to the first one.


Frame for the stove bottom:

Build with the four parts (17,18) a rectangular frame. Join them together with four frame joints (19) using eight nails (29) each.  Results: a square of 66.5 x 66.5 cm (see Diagram 5).

Fasten on each sidewall (20)--each time on the same side--one leg (21), each with three nails (29). Also attach one reinforcing strip (22), with five nails (29), according to Diagram 9.

Fit up the four sidewalls one after the other with six nails (29) each to the frame of the stove bottom and join them together at the legs, so that a stiff and rigid body results.

Stove bottom (trough):


Fill the cavity between the sidewalls and the trough will insulation material (34). With loose material be sure to push in enough so that no cavities are left which might set or sag in time. However, do not cram too much because there must be enough air space in-between the fibers for the best insulation.

Before attaching the floor (23), you must cut out the recess for the legs in all four corners.  The floor is fastened without glue with five screws (24) per side, so that it can be removed easily later to replace the insulation.

Window lining:

To fix the revetment (13,14), first put the window in the right position on the frame. Place the four parts narrowly adjacent to the frame for the glass, so that the parts for the frame of the stove bottom overlap in the corners, and nail them down with nails (30). See Diagram 11.

Final touches:

Fasten with four screws (26) a handle (15) in a comfortable position. Fix the other two handles at both sides on the revetment with four screws (27) each.

A locking device should prevent the window from shifting when it is opened. This consists of two window support ledges (11) and two buffer blocks (12). The ledges are fixed on the back of the glass frame with three screws (24) each, so that they protrude 2 cm on each side. The buffer blocks are screwed onto the lateral revetment with two screws (27) each adjacent as well to the frame for the glass as to the window support ledge (11). See Diagram 5.

The whole finished solar cooker should be treated with a weather protection (35).


Again, this is only one model for the wooden cooker. Kenyan artisans have constructed their own cookers merely by seeing a functioning cooker. ULOG has plans for other cookers, including family-sized models, that can be obtained directly from the organization. Dimensions may vary, but the cooking area should not be much smaller than the dimensions given or the cooker will not be able to function properly.

Other variations include:

1.      using aluminum foil mounted on wood for the trough or sheet metal on the reflector rather than foil. Off-set printing sheets can be found relatively inexpensively, compared to store-bought aluminum. Aluminum paint instead of foil or metal is not recommended: I tried it and ended up covering the paint with foil.

2.      a front-loading device. This model seems to be more difficult to build but will prevent heat loss when opening the oven. (Heat rises, therefore escapes readily when a top-loading cooker is opened.)

3.      no- or multi-reflector cookers. The number of reflectors can be varied according to the owner’s preferences. Cookers without reflectors will cook slower in the morning and late afternoons; cookers with many reflectors may cook faster but require greater attention.



Pasteurizing Water

Water can be cleaned to kill germs in a solar cooker. It need only reach 65 degrees Centigrade, not to the boiling point.  Fill the containers almost full with water and cover loosely. After pasteurizing, store the water in the same tightly covered  vessels to keep it clean. A Water Pasteurization Indicator (WAPI) can be used as well. Cooking time:  3 hours for 4 liters.


Fresh milk must be boiled to kill any germs within. This can easily be done with a solar cooker. However, if left too long (i.e., all day) the milk will be scalded.  Cooking time: 1 hour per liter.


Mix 2 parts of cold water and one part milk. Add sugar (this can wait until serving) and tea leaves. Stir upon removing from the cooker; it will look white and uncooked until the leaves are mixed. Cooking time: 45 minutes for 1 liter (3 servings).



Mix 1 part rice to 2 parts water. Add a little cooking oil or fat. Place in the covered pot. Cooking time: 1.5-2 hours.


Mix one part maize meal with one part cold water. Stir well to avoid lumps in the ugali. Add salt if desired. Do not open the cooker to beat of flip the ugali. The pot is much easier to clean than with traditional cooking style. Cooking time: 2-2.5 hours.


1 liter spaghetti sauce   parmesan cheese

.5-1 kilo each ricotta and shredded mozzarella cheese  .5 kilo lasagna noodles

In bottom of roaster pan, pour 1/3 of the spaghetti sauce. Coat uncooked noodles with ricotta cheese and make a bottom layer in the pan. Add half the mozzarella.  Repeat to make a second layer.  Top with remaining spaghetti sauce and parmesan cheese. Cover and bake. Cooking time: 4 hours.

Fruits and Vegetables

Mixed Vegetables

A variety of  vegetables can be prepared in a similar fashion, alone or mixed. Wash and cut vegetables like cabbage, carrots, tomatoes, green beans, potatoes, cauliflower, brocolli, eggplant, mushrooms, etc. Cut onions, and meat if desired, and fry in fat. Add all the prepared vegetables along with 1 cup water, salt and spices (beef cube) to taste. Stir well, making sure that all vegetables are wet. Cooking time: 2.5-3 hours.

Cooking Bananas

Place the green bananas into the pot without any additional water. (The peels with maintain enough water.) Peel before eating. Cooking time: 2 hours.

Bananas Deluxe

Fry meat (minced), onions, and tomatoes in fat or cooking oil. (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.) Peel and cut (dice) bananas. Add potatoes as well, if desired. Add to the meat, stir well, and add 1 cup water, salt, spices (beef or chicken cube), half a teaspoon sugar. Stir so that all the bananas are wet. Cooking time: 2-2.5 hours.


Soak beans in cold water overnight. Fry onions and tomatoes in fat. (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.) Add one part soaked beans to one part maize, enough water to cover all the food and then more (it will absorb water as it cooks), salt and other spices to taste. Stir well so that all the ingredients are wet. Cooking time: 3-5 hours, though the longer you cook it, the better.


Fry onions in fat.  (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.)  Wash mushrooms very quickly to make sure they do not absorb too much water. Cut into thin slices and add to the onions. Sprinkle with 1 teaspoon of wheat flour, stir well, then add a half cup of water, half cup of milk, and salt and spices (chicken cube) to taste.  Stir again. After the food is cooked, add a teaspoon of butter to increase the creamy taste. Very good with rice or ugali. Cooking time: 45-60 minutes.

Pineapple Yams

Peel and dice yams.  Add pineapple chunks and a cup of juice. Bake uncovered. Cooking time: 2 hours.

Boiled Potatoes

Wash potatoes of similar size and place them, still wet, into the pot. Add very little water into the pot (approximately .5 cm).  Cooking time: 2.5 hours.

Baked Potatoes

Wash medium sized potatoes, rub the skin with fat or cooking oil, and place them into the pot without extra water. After 2-2.5 hours, remove the lid from the pot and bake another 15-30 minutes to achieve the typical "baked" look.

Sweet Potatoes

Cook the same as the boiled potatoes: Wash the potatoes well and place them wet into the pot with 2 cm water. Cooking time: 2-2.5 hours.


Fry quite a lot of onions and a bit of finely cut garlic. (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.) Add the washed and cut zucchini, green peppers, eggplants, and many tomatoes to the pot, along with one cup water, salt and spices (beef or chicken cube) to taste. Stir well, making sure all the vegetables are wet. Cooking time: 2-2.5 hours. Ratatouille goes well with ugali or rice.

Sukuma Wiki / Spinach

Wash the leaves, removing the stems and bad parts. (For the spinach, keep the stems, for higher nutrient content.)  Chop leaves. Fry meat, onions and tomatoes in fat. (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.) Add the wet sukuma and a half cup water, salt and spices to taste.  Cooking time: 1.5-2 hours.

Vietnamese-style Vegetable Soup

more than 1 liter water   tofu, pressed dry and cut into strips (opt.)

4-5 Tbsp. tamari or soy sauce     green or red chilies to taste

juice from 1/2-1 fresh lime (or lemon)     mint leaves (4-6 per bowl)

4-10 cloves of garlicwatercress (1 bunch per bowl)

4 large slices of fresh gingercilantro (1 small bunch per bowl)

1 large onion, sliced in strips       basil leaves, fresh (2 per bowl)

1 carrot, thinly cut diagonally      mushrooms, fresh (a few per bowl)

All ingredients except the mint leaves, watercress, cilantro, basil leaves, and mushrooms until the carrot is almost tender. Remove cooked ginger. Pour into bowls.

Proteins (Meat and Beans)

Beans are generally presoaked in cold water overnight to soften the outer coat and therefore reduce cooking times. This, however, is not absolutely necessary, though allow for longer cooking times if they’re not soaked.

Beans (mungbeans, red beans, etc.)

Soak the beans in cold water overnight.  Fry minced meat and onions in fat. (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.) Add sliced tomatoes and chopped bell peppers. Stir well and add the soaked beans, cover with water and add an extra cup, salt and spices (chili cubes, etc.) as desired. Stir again. Cooking time: 3-4 hours, though the longer it cooks, the better.

Baked Chickpea Casserole

Soak beans in cold water overnight.  Cook beans until tender; drain. Add the rest of the ingredients and cover. Bake again until tender. Serve with bread (preferably pita). Cooking time: 3.5-4 hours (??).

Boston Baked Beans

Soak beans in cold water overnight. Cover beans with cold water, adding all other ingredients.  Stir to mix. Leave the onion whole and push it down into the center of the pot. Cover and cook, adding water if needed. Serve with brown bread and cheese. Cooking time: 4 hours (?).

Refried Beans

Soak beans in cold water overnight. Combine all ingredients and bake. Drain but save the liquid. Mash the beans adding liquid to get the desired consistency.  Add seasonings to taste--cumin, salt, garlic, pepper, etc. Cooking time: 4 hours.

Spicy Mexican Beans

Soak beans in cold water overnight. Cook beans until tender; taste and adjust seasonings as necessary. Put grated cheese on top and cook until melted.  Serve with rice and corn tortillas or cornbread. Cooking time: 3-4 hours.

Turkish Lemon Beans

Soak beans in cold water overnight.  Put beans in pot with water, salt, and onion. Cook until almost tender. Add the rest of the ingredients and cover. Continue cooking until tender. Cooking time: 4 hours.

Boiled Eggs

Wash the eggs and place them in the cooker and cover them with a black cloth (or place them without water in a pot). Cooking time: 20 minutes to 1 hour. If you leave them all day in strong sunlight, they may burst.


Wash the fish or fillets in fresh water. Dry them in a clean towel or household paper. Rub the fish with a little salt and pepper on both sides. Cut onions and tomatoes in slices and sprinkle them with a little salt, pepper, and spices. Fry the fish on only one side and then turn it over. Dress the cut onions and tomatoes in the pot around the fish and add very little water, about 2 or 3 spoons full. Serve the fish together with rice or potatoes. Cooking time: 1-1.5 hours.


Cut the chicken into nice portions, rub them with salt, pepper, and other spices. Fry the pieces shortly on both sides (with a regular cooker). Remove the chicken, then fry cut onions, sliced tomatoes, and/or sliced mushrooms in the same fat. Add the chicken back into the pot and one cup of water, pepper, and other spices (chicken cube). When serving, taste the soup and add additional salt, if required.  Cooking time: 2-2.5 hours.

Meat (Beef, Lamb, Pork, Goat, Rabbit, etc.)

Chop onions and garlic, and add to the minced meat. (The larger the pieces of meat, the longer the required cooking time.)  Fry with cooking fat. (This can be done on a regular cooker or in the solar cooker before the rest of the ingredients are added.) Add, if you like, a small amount of cut cabbage, 2 to 3 medium carrots, 4 to 5 sliced tomatoes, and green pepper. Stir well. Add salt, pepper, and other spices (beef or chili cube) to taste.  Add very little water, only the amount you would like as soup when the cooking is finished. Stir well again to be sure everything is wet. Cooking time: 2.5-3.5 hours, though the longer you cook the meat, the more tender it becomes.


Spread termites (preferably already dead) onto a baking pan. Cook until done.


Baking requires a lot of heat, so choose a clear, sunny day and preheat cooker for an hour or so before baking. I recommend putting the food in before 11 am, though baking in the afternoon or even twice a day has been done.

Banana Bread

In a bowl mix flour, salt, and baking powder. In a separate bowl, beat butter and sugar until light and creamy. Add the bananas. Now alternately adding the banana mixture to the flour mixture in three shifts, also add, slowly, milk (or water) and vanilla. Stir until blended, then fold in chopped nuts. Optional: spices, such as cinnamon, nutmeg, cloves, can be added for flavor; the bananas can be soaked in one cup of strong black coffee for an hour before mixing into the batter. Pour the dough into a slightly oiled loaf pan (or pot) and only partially cover the pan with the lid, leaving a 2 cm opening. Cooking time: 2.5-3 hours.


Blend flour and salt.  Add oil (or melted Blue Band).  Add water as necessary to make it manageable. Roll out into approximately 1/2 cm thickness. Sprinkle seeds on top, using egg to make it stick. Bake until golden brown. Cooking time: 3 hours.


Prepare yeast according to instructions on package (usually dried yeast powder requires mixing with 4 times its weight of warm water). Let this rise for 10 minutes. Do not use the solar cooker to hurry this, as the dough will harden and a crust will form, inhibiting the rising process. Pour the flour into a bowl or a clean smooth surface. Dig a small hollow in the middle of the flour and pour the liquid yeast in it.  Mix some more of the flour with the rising yeast and let it rise again for a few minutes. Now begin mixing carefully all the flour with this yeast mixture and slowly add the water/milk and salt until you have a nice, smooth dough. If the dough is too wet, add more flour.  Put the dough back into a bowl, cover with a clean, damp cloth and let it rise in a warm place for about an hour.  After kneading the dough for a second time, form it and place it into a cake pan or pot which had been rubbed with fat and dusted with flour. Place it in the preheated cooker with the pot not completely covered---leave a slit of about 2 cm. Cooking time: 3 hours.

Fancy Bread

Mix all ingredients together well, and smooth into dark pan, Cover. The last hour can be uncovered if using dark grains. Cooking time: 3-4 hours.


Melt shortening and chocolate together (25-30 minutes in solar cooker). Cool. In a separate bowl, beat eggs until light. Stir in sugar, then chocolate mixture and vanilla.  Add dry ingredients and mix well.  Add nuts last. Pour into greased round pan. Cooking time: 2.5 hours.

Coconut Cookies

Beat egg whites until very stiff. (Add a pinch of sugar to make it go faster.) Add carefully sugar and coconut flakes. Mix well.  Drop mixture with a teaspoon onto a very lightly oiled pot lid or other flat plate and place in the preheated cooker without covering. Cooking time: 1 hour.


Mix all ingredients.  Sprinkle with nutmeg. Cover and bake. Cook before serving. Cooking time: 1.5 hours.

Baked Fruit (and Meringue)

Cut up fruit, removing pits, cores, and bad parts. Places slices into a pot. Sprinkle brown sugar and cinnamon on top. Cover. Cooking time: 1 1/2 hours or longer.

Meringue topping:  Beat egg whites until stiff, adding vanilla and sugar while beating. Spread on top of cooked fruit and return to cooker, uncovered. Serve hot or cold. Cooking time: 1 hour.


Mix together everything except oil and honey. Add oil and honey last; stir occasionally while baking. Cooking time: 2-3 hours.

Hot Fudge Sundae Cake

In a pot, mix flour, sugar, cocoa, baking powder, and salt with a fork until smooth. Fold in milk, salad oil, vanilla, and nuts.  Beat until smooth. Pour hot water over batter. Bake. Cool for 15 minutes before inverting onto serving plate. Top with ice cream (!!!) and spoon hot fudge sauce over all.  Cooking time: 1.5-2 hours.

Maize Cake (Cornbread)

Mix the maize meal, sugar, baking powder, and salt in a bowl and add the raisins and lemon peel.  In another bowl beat the eggs, add the oil, and mix well. Add this mixture to the flour mixture and knead well by slowly adding the milk until you have a slightly wet dough. You may need additional liquid, but only add a little at a time; the dough should not be too wet. Fill the dough into a greased cake pan or pot. Put in the preheated cooker, without covering the pan completely with the lid--leaving a small gap (2 cm). Cooking time: 2.5-3 hours.

Oatmeal Squares

Cream together egg, honey, and vanilla. In a  separate bowl, sift together flour, soda, and nutmeg. Add butter, nuts, and oatmeal to flour mixture. Add creamed mixture. Mix well.  Pour into greased pot. Cooking time: 1-2 hours.

Roasted Nuts

Spread nuts onto a flat dish or pot lid. Sprinkle with salt if desired. Can be covered with a black cloth to hide the treat from prying fingers. Cooking time: peanuts, 2 hours; almonds, 1 hour.

Alternative Uses

  1. Disinfecting equipment. Medical objects, such as bandages, can be disinfected by using a solar cooker and water heated to the boiling point. Items that must remain dry can also be sterilized once the cooker reaches 149 degrees Celsius (300 degrees Fahrenheit), so a thermometer is necessary.

  2. Preserving ("canning") foods. This is a tricky process that can be dangerous if improperly done, so please be sure that you reference other sources or have experience canning.  Fill the jars with the fruit, water, juices, etc., and loosely cover. Heat in the cooker until the liquid begins to boil over. Tighten the lids and remove from the cooker to cool.  (Reference s include The Expanding World of Solar Box Cookers by Barbara Prosser Kerr.)
  3. Fireless cooker.  The "haybox" cooker has been in use for a long time. Cook the food in a covered pot until it has boiled briefly (varies with the food; in Kenya, most foods require 5-15 minutes), then quickly place into the cooker, surrounding the pot with pillows or other insulation.  There should be little or no free air space. The trapped heat will continue to cook the food slowly, as it cannot escape.
  4. Drying foods. Place a tray of food to be dried on top of the glass / polythene window, in front of the reflector.  Inside the cooker, the moisture will not escape, and the extra light from the reflector discourages insects.  If insects or larvae are still a concern, spread the dried fruits into a preheated cooker and cook for 20 minutes, stirring once half way through.

For the purchase of solar cookers, WAPIs, or publications, or for further information, contact the following agencies:

TransWorld Radio (TWR) Institute of Cultural Affairs (ICA)

(solar cookers)

Box 21514 

(02) 560552, 560572, 560574        

(solar cookers, courses)

Box 21679

(02) 724314, 729375

Solar Cookers International (SCI)      



Box 2647
Littleton, CO 80161 USA

Children's Earth Fund
40 West 20th Street
New York, New York 10011 USA

(212) 727 4493

Verein zur Foerderung kleintechnologischer

(assistance--technical, financial)

Postfach CH 4011
Basel, Switzerland CH-4054  

Nutzung von Sonnenenergie (VKSE) Gruppe ULOG

  (construction models)

Morgartenring 18
Basel, Switzerland

Kerr Enterprises