A detailed numerical simulation of the performance of household refrigerator having a top-mount configuration is made in this study, and an experiment is carried out with a real refrigerator for verification. The results indicate the temperature distributions from the numerical simulation are qualitatively in line with the experimental measurements. Cyclic temperature variations occur amid freezer, refrigerating, and vegetable compartments due to on/off control strategy. However, it is found that the temperature variation for freezer and refrigerating compartment are in phase with each other while the temperature variation in vegetable compartment is roughly out-of-phase with the other two compartments. The simulations show that the design of air duct and its locations may impose a detrimental role on the temperature uniformity within the refrigerator, yet the airflow is strongly influenced by gravity. It is also found that the refrigerating compartment possesses the worst temperature non-uniformity. For improving the temperature non-uniformity, a modified design incorporating the air duct design with appropriate locations of the inlet openings in the freezer and refrigerating compartment is proposed. Though these modifications the maximum temperature difference and the root mean-square of temperature variation in refrigerating compartment, had been reduced from 7.17 °C to 3.57 °C and from 3.17 °C to 1.55 °C, respectively.