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A solar cooker or oven is a hot box where solar energy is concentrated to heat and cook food.  Solar cookers are used in rural areas, where LPG cylinders are unavailable .Time spent gathering firewood for cooking  is saved and trees need not be cut down for wood.

The solar cooker consists of  an outer box, an inner cooking box , mirror, double glass lid and a thermal insulator. The inner cooking tray is made from aluminum and is coated with black paint to increase the efficiency of  absorption of solar energy and transmission of  absorbed energy to the cooking utensils. The mirror increases the radiation in the box by concentrating the solar light. The outer surface of the utensils are painted black to maximize the heat absorbed and minimize the heat radiated. The thermal insulator reduces heat loss.

The temperature inside a solar cooker can reach 150 Deg. Celsius, which is less than that of a conventional oven. However, this temperature is sufficient to cook most meals, only the cooking time will be longer (almost twice as long in some cases) . The time taken depends on the time of  the day and intensity of  sunlight.

Box type solar cookers with a single reflecting mirror are promoted in India by the Ministry of  Non-Conventional Energy Resources. They are available at subsidized rates if they conform to BIS standards and are manufactured by about 40 manufacturers in the small scale/ tiny industries sector. A solar cooker usually lasts for about 10 years.

 In community type solar cookers, food is cooked for hundreds of people simultaneously. The position of  the reflectors is changed according to the position of the sun. Community type solar cookers are not used very widely.