Q&A for How to Make and Use a Solar Oven

Yes! As long as it’s a bright, sunny day, the solar oven should work even if it’s cold out. Since it can take a long time to make food in a solar oven, you’ll have to time it carefully to take full advantage of the relatively short daylight hours in winter.

One of the main disadvantages is that you need plenty of sunlight for your solar oven to work, so it won’t be much use on an overcast day. They also don’t get as hot as a regular oven, and can take a long time to cook.

There are a lot of things you can do, as long as you stick to dishes that don’t need to be cooked at higher temperatures. A few options include baked beans, simple cakes and cookies, smores, and English muffin pizzas.

You could possibly use bread, but maybe a less dense food would work better.

The black paper absorbs the light and tinfoil would just reflect it.

It depends on the style of solar cooker you make. If it's made out of a box, it will be a pretty quick build. Easy to complete in an afternoon, though you could slap a simple one together in half an hour. If you go more complicated, with more reflectors and insulation around the box, it could take much longer.

Foil, like Mylar, helps to reflect heat and light. Many solar farms work by redirecting light to a central point, which will vaporize water, and the steam from that process drives a turbine. Similarly, you are using the foil to direct the light to a central point, usually a black pan (black absorbs light, and thus gives off the most heat when light hits it). An added bonus in close quarters is that the foil helps reflect heat radiation towards the center as well. Everything warm gives off heat radiation (aka infrared radiation, or thermal radiation). That is why you can feel heat from a fire without touching a fire.

Heat and light. Reflecting/catching enough light to cook what you want, and keeping that heat in. Many solar cookers have a greenhouse effect going on with glass or plastic. Several of the bigger box designs have a layer of insulation between the boxes to help keep heat in. Foil will help reflect light and heat.

The length of time may vary depending on the food you are cooking, and the amount of sun you are getting. If you aren't getting much sun, it may take longer. Just try to place the oven where you get the most sun.

Use a plain box painted black. Cut a hole in the top that's about the size of an iPhone 5. Cover the hole with clear plastic wrap.

It does. For any beginner, it would be better to make the simple one and not the heavy-duty one. The simple oven won't cook as much, but it will be easier for you to make.

As big as you need it. Width, length, height, volume, and area all depend on your needs.

Solar ovens have about the same cooking time as a regular oven, so about the same time as normal.

Yes, it is as reflective as aluminum foil and would still reflect sunlight.

Yes, as it also reflects light. It would be helpful if you don't have any reflective bubble wrap.

You'd save money on electricity, and it's something portable that can be used while camping or at the beach.

Probably yes, because it has the same concept as this one. Just make sure that you have it in the size you need and follow the instructions outlined above.

I don't think it matters, as long as it is in enough sunlight.

It would take about 30 minutes or so, as long as it is for one of the advanced solar ovens. If you make a simple solar oven though, it would take about 4 hours.

Yes as long as it gets hot enough––212°F (100°C). It will take a few hours for it to cook thoroughly.

Yes they can do it just like a regular oven! They can cook anything a regular oven can, only it will be much slower.

Yes, it's ideal for a science fair, especially if you can demonstrate its use.

Probably not too much, it would be just in the one spot. Magnifying glasses are usually small, so with exceptions depending on size, it would only speed up the process marginally.

It is possible, it may take a little bit of time. It is a smart idea to place the chocolate bar in a bowl to prevent the chocolate from spreading everywhere in the oven.

It depends how hot your oven gets, and how hot the cake needs to be baked at. You don’t want to bake your cake at a low temperature for a long time because it won’t cook properly.

A bonfire is really the best way to do this. However, if you must use a solar oven, it would probably take about 20 minutes if you're making smores.