What Are Solar Ovens – and Why Are They Heating Up?

Solar oven
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Solar ovens are devices that gather sunlight and create heat to cook food without other fuel sources. Popular with homesteaders, off-the-grid enthusiasts, and environmentalists, solar ovens are also an affordable and sustainable cooking method that can be used in isolated communities and rural areas in the developing world. Among its many benefits, solar energy is a clean, renewable source, which also helps prevent deforestation, fossil fuel usage, and greenhouse gas emissions.

There are many different designs, but solar ovens typically fall into three primary categories: box ovens, panel ovens, and parabolic ovens. Box ovens reflect sunlight directly into an enclosed container; panel ovens create heat through strategically positioned surfaces and direct it to a separate container; and parabolic ovens use a curved surface to concentrate sunlight to a single point. Most ovens can be moved easily, set up anywhere with sunlight, and DIY versions can be made at a very low cost.

How Solar Ovens Work

Solar ovens gather sunlight and direct it into an enclosed surface, where the trapped heat gathers. The exact process varies depending on the design, but all solar ovens require highly reflective materials (such as mirrors, polished metal, or aluminum foil) set at particular angles to gather light. They also need to retain heat well, separating outside air from the air inside the cooking vessel. Box ovens often have a glass lid (DIY versions might even use clear plastic wrap) to allow sunlight into the oven and, in a process similar to the greenhouse effect, retaining heat inside.

Solar cooker
Solar cooker in Tengboche Monastery, Khumbu, Nepal. John Elk III / Getty Images

While there are dual electric/solar ovens available, with an electric hot plate at the base for overcast days, the majority of solar ovens won't function at night or when it's too cloudy.

Reasons to Choose a Solar Oven

There are many different reasons people choose solar ovens, including their safety, sustainability, and reliability.

Economic Benefits

Some high-end solar ovens aren't cheap, but DIY options can be made with items people have at home, like aluminum foil, plastic wrap, and pizza boxes. After the initial purchase cost, even expensive solar ovens remove the cost of cooking fuel, meaning there are long-term cost reductions.

Safety Benefits

Solar ovens work without electricity, making them a great option for hurricane preparedness kits and situations when areas could be without power for an extended period of time. Because they also don't require a fire, they're considered safer than burning wood or other materials. That doesn't mean there are no risks, however. In particular, parabolic ovens reaching intense temperatures frequently need close supervision, and it's important not to seal cooking jars too tightly or they could explode.

Environmental Benefits

Solar energy is a renewable resource; it is less environmentally harmful to cook food with this energy source when compared to non-renewable sources like wood and fossil fuels. Using sunlight to produce heat means less air pollution, as wood isn't burned and petrochemicals aren't being processed for fuel. Less wood for fuel also means less deforestation. Using sunlight exclusively is the solar oven's greatest asset as well as its biggest drawback—reaching cooking times comparable to conventional ovens requires significant sun exposure, which isn't possible in many cases.

Tips for Using Your Solar Oven

Selecting the right solar oven first requires determining what you'd primarily like to cook. The most basic DIY varieties are great for S'mores, but they won't sear a steak. For all types of ovens, it's ideal to have a thermometer, if one isn't integrated into the oven's design. It's also important to consider if you plan to travel with your solar oven, as some types are much lighter and easily broken-down for transport than others. Until you become confident using your solar cooker, it's best to prepare vegetarian foods. Here are some important tips for different types of solar ovens.

Box Ovens

Solar Cooking in Southern California
Bread and rice cooked in a solar oven with an average temperature of 250-300 degrees in Borrego Springs, in Southern California. Corbis via Getty Images / Getty Images

Box ovens typically contain the most space for cooking and can often allow multiple pots of food to be prepared at once. The clear surface on top of the box should always be kept clean to allow the maximum amount of light to enter the container. Try to avoid opening it, as that will release heat. That said, if steam obscures the top of the box it could reduce how much sunlight can enter, and it will need to be released.

Use dark, shallow, pans, as that will help absorb optimal sunlight. These solar ovens are great for baking, cooking beans, or foods that require a longer cooking time. You can place a dark brick or stone inside and place the box in the sun to preheat.

Panel Ovens

Panel ovens are ideal for people on the go, typically lightweight and easy to transport. That said, they don't reach the temperatures that box and parabolic ovens can. When using these ovens, work with a dark pan or glass jars that have been painted black. These containers are then often placed in a sealed oven bag or some sort of clear, oven-safe enclosure to further concentrate the heat.

Cooking in a solar oven on the grass.
zianlob / Getty Images

Parabolic Ovens

Because these ovens concentrate heat to a single point, they can reach a high temperature quickly; however, maintaining that temperature requires turning as the sun changes positions. Dark-colored, tightly sealed vessels are ideal for this method, commonly used of rural Chinese provinces to boil water for purification. Parabolic ovens require a closer eye than box or panel ovens because they can reach higher temperatures much more quickly.

View Article Sources
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  2. "Solar Explained." U.S. Energy Information Administration.

  3. "Using Solar Ovens in Rural Communities in Nyakach Region to Mitigate Climate Change—Kenya." United Nations.

  4. Clarke-Sather, Abigail R., et al. "Analysis of a Rural Northwestern China Household Energy Use Survey Focusing on Parabolic Solar Cooker Use for Water Purification." Journal of Sustainability Research, vol. 1, no. 2, 2019., doi:10.20900/jsr20190009