This paper investigates a production management method to verify thermal performance of ALC panels by measuring thermal conductivity of ALC base material sampled from the same production lot. The thermal performance of ALC panel specimens manufactured with different levels of reinforcement were measured using calibrated heat box method and compared with the thermal conductivity of the non-reinforced ALC specimens of the same production lot. The comparison has suggested that apparent thermal conductivity of ALC panels exhibit 0.02 W/(m・K) increase at maximum in comparison with the thermal conductivity of non-reinforced ALC material of the same lot and moisture content.