One of the many methods used in the production of plastic materials is plastic injection method.The plastic injection method needs equipment difficult to choose, and it is also costly. Manynegativities could be experienced during production. One of them is the water droplet problemson the surfaces of the mold. Provision of insufficient cooling on molds, ambient temperature,non-homogenous humidity, mechanical and other stresses occurring during production, crackson the product, warpage and thermal residual all cause some stress-like defects. In this study,the effect of water droplets problem on production efficiency in the molds of PolyethyleneTerephthalate (PET) raw materials manufactured in a private enterprise was examined. Thepercentage productivity table has been created based on different months of the year, AugustJuly and August. In the enterprise, 8 dehumidifiers were placed to 17 injection machines tocreate a homogeneous production temperature in the environment. Humidity and heat valuesobtained during production were monitored daily and recorded. In this study, which wasconducted over two years and three months, positive results were obtained suggesting that thewater droplets formed in injection molds has decreased with the effect of dehumidificationdevices, and the efficiency of injection production has also increased by 8%.