Air conditioner has been one of the main necessities for mankind, especially for people living in warm climate countries such as Indonesia. The need for air conditioner itself functions for the comfort of users and also operating functions of certain equipment. Due to global warming, increase in the temperature of the Earth forces greater energy consumption of air conditioner to reach the required room temperature requested by the user. This increase in energy consumption has been the main focus of the Indonesian government in finding solutions to help reduce energy consumption from non-renewable energy power plants while still fulfilling societies demand. One solution is applying energy labelling for air conditioners using Energy Efficiency Ratio (EER) as a parameter. In order to calculate the EER of air conditioners, a controlled room environment is needed, thus the reason of creating the Psychrometric Chamber. One of the required data to calculate EER is the temperature of air leaving the evaporator which will take part for the cooling capacity calculation, thus the reason for constructing the Air Sampler. The Air Sampler collects data of dry bulb temperature and wet bulb temperature of air exiting the evaporator and also the Psychrometric Chamber room. Certain calculations are needed in designing the Air Sampler which involves fan selection, pipe selections, and sensor selections. Besides calculation, the design of the Air Sampler needs to follow standards where applicable. Overall, this paper shows the design process and construction of the Air Sampler in the Psychrometric Chamber to calculate the EER for energy labelling.