The typical error of thermoelements of ±1% ×ΔT in other work was reduced to ±0.5% ×ΔT by batch consistency and polynomial calibration. For determining the power consumption under standard conditions (average temperature of the fresh- food compartment Tm =5 °C,ambient temperature Ta =25 °C and humidity 50%), energy meters type EZI 1 (Zimmer Electronic Systems) with 25 pulses/Wh were used,leading to a relative measurement error of about