Cooking accounts for a significant share of the worldwide energy consumption issue. Solar box cookers are a good alternative in mitigating fossil fuels and biomass use, especially for tropical developing nations like the Philippines. Still, their broad acceptance is limited by their high dependence on sufficient sunlight for better performance. Thus, this research aims to develop a thermal-efficient, portable solar box cooker with sand-sensible heat storage materials, coconut coir (Cocos nucifera) agricultural waste insulators, and locally sourced building materials. The designed and constructed cooker was evaluated using three thermal performance tests: the Stagnation Temperature test from the Bureau of Indian Standards (BIS), the Cooking Power test from the American Societal of Agricultural Engineer (ASAE) Standards, and a rice cooking test. Data obtained from the three-day trials of each test were used to determine the first figure of merit (F1), the single measure of performance (Ps(50)), and its ability to cook 300 g of NFA rice with 500 mL of water, respectively. It was found that the cooker achieved an F1 of 0.06 Km2/w, a Ps(50) of 6.651 W, and cooked rice for one-third of the tests. Obtained experimental findings showed that the device is marked as a Grade-B solar cooker. Results indicated that the solar box cooker is capable of pasteurizing water and cooking rice
