At an ambient temperature of 30 °C, the effect of door opening caused compartment temperature rose by 14.5 °C for fixed frequency HRF A and by 6 °C for variable frequency HRF B, as shown in Fig. 1 and Table 2. In Table 2(A), the temperature fluctuation, Tmax−Tmin, is the difference between average maximum temperature and average minimum temperature for the specific compartment as the HRF under operation. But the calculation for average of compartment temperature did not include the temperature variation during defrosting cycle. The measured temperature values in Table 2(A) are compliant with CNS test standard [4] used in Taiwan. The average temperatures of food compartments for samples HRF A and HRF B were all within 3.0 ± 0.5 °C, which the average temperature of freezer compartment for each HRF samples was within −18.0 ± 0.5 °C under specific testing standard [4]. Comparing the temperature uniformity inside HRF cabinets, variable frequency HRF B has less temperature variation in food compartment than that of fixed frequency HRF A by 0.9 °C. Variable frequency HRF B has less temperature variation in freezer than fixed frequency HRF A by 3.7 °C. In general, the variable frequency HRF B has much more potential for stable control of storage temperature and efficient operation.