Effects of air temperature and humidity on sleeping women by the ventilation and air-conditioner, Japan

The effect of ventilation system on the sleeping persons has not been well studied. This is because mechanical ventilation systems had not previously been widely used in residential buildings in Japan. However, 24-hour mechanical ventilation is now mandatory in highly airtight and insulated houses. This study compared the temperature and humidity in bedrooms using either regular mechanical ventilation or desiccant ventilation when the air conditioner was switched off by a timer. The experiments investigated the sleep quality, thermoregulatory responses, and thermal comfort of young woman participants during the sleeping period at night. The desiccant ventilation reduces the air temperature and humidity by 1 °C and 20% Rh, respectively. While the air conditioner was turned off, the women’s skin temperatures increased by about 0.5 °C, but did not increase awakenings, as a result, the sleep efficiency was maintained at 96%. Thermal and comfort sensations were obtained significantly on the cooler and more comfortable side with the desiccant ventilation system than without desiccant system.