Thermal insulators of sandwich panel play a significant role in reducing energy consumption in buildings and industry. The ultimate performance of sandwich panels depends on the type of core and the facing materials. In the present study, the simultaneous combination of four insulating layers—polyurethane,,EPS (expanded polystyrene),, ABS, and bubble foam—in the sandwich panel structure of a refrigerator wall was experimentally investigated. The number of layers and the thickness of each of the aforementioned materials can affect the heat transfer coefficient and, consequently, the compressor off-time duration of the refrigerator. The Taguchi method was employed to design the experiments involving different numbers and thicknesses of the four materials. A bi‑objective optimization was considered, including maximizing the compressor off‑time and minimizing the manufacturing cost (as the thermal performance and economic criterion). By constructing a refrigerator box and embedding the insulation layers according to the Taguchi‑suggested layout in one of its wall, the compressor off‑time was recorded. The results showed that, if cost is not taken into account, the sandwich panel consisting of one EPS layer, one 8‑mm polyurethane layer, one ABS layer, and one 8‑mm bubble foam layer yields the longest compressor off‑time. However, when considering the foam manufacturing cost, the optimal sandwich panel comprises one EPS layer, one ABS layer, and one bubble foam layer without the polyurethane layer. Moreover, compared with insulations containing EPS, polyurethane, and ABS without bubble foam, the optimal insulation achieves a 25% reduction in energy consumption.