Refrigerated infrared detectors have a wide range of applications in military, industry, medicine, and other fields. Dewar components are composed of chipsets and dewars. A dewar can provide the necessary and reliable working environment and optical, electronic, and mechanical interfaces for the chip. When designing dewar components, the thermal power consumption of the chipset, static heat load of the dewar, thermal mass of the dewar, and heat transfer temperature difference must all be calculated to facilitate the selection of refrigerators and ensure the realization of indicators such as refrigeration time and power consumption under the working conditions of the full temperature zone. Currently, the calculation of indicators is manual; however, these processes are prone to errors and have low efficiency. Therefore, this paper proposes a method that utilizes software to calculate thermal power consumption according to relevant theories and uses the C# language to develop software. This software provides support for improving the accuracy and efficiency of thermal design. It also provides key indicators for the selection of refrigerators and the overall performance guarantee of the components. With further refinement, this method is expected to become more accurate.