In the indoor side, compartment air is cooled and dehumidified by a room air conditioner for test. Then, the air is heated and humidified to be balanced at the temperature and humiditiy as specified in GB&ISO by means of an air handling unit. The amount of calorie and moisture to be supplied for this purpose is measured. In the outdoor side compartment air is heated and humidified by a condenser of air conditioner for test. Then, the air is cooled and dehumidified to be balanced at the temperature and humidity as specified in GB&ISO by means of calorie and moisture to be supplied for this purpose is measurd.