The temperature and moisture distributions in a dry room with a heat and moisture source -i.e., workers- are studied numerically by using a standard $k-varepsilon$ turbulence model. In order to evaluate the effectiveness of heat and moisture ventilation inside the room, the heat removal capacity and the moisture exhaust efficiency are introduced. The effectiveness of ventilation control is analyzed by evaluating the temperature and humidity distributions in the room quantitatively. It is found that the mean absolute humidity inside the room is almost constant regardless of the models and the heat generation rates in this study range. This results from the fact that the moisture generation by the workers was relatively small. Through the modification of the design, 40% improvement in critical decay time was achieved.