Experimental study on effect of low humidity prevention strategy in winter in highly insulated and airtight house

As highly insulated and airtight houses have built popularly, the problem which indoor air becomes low humidity in winter, is paid attention. The problem is caused by rise of heating level and increase of ventilation amount by mechanical ventilating equipments, etc. ¹⁾ Then, to clarify the actual condition of indoor low humidity in winter, we monitored the actual humidity environment in 29 occupied houses in the Tohoku region and Niigata, Japan, from 2001 to 2006. As the result, it is found that the indoor low humidity in winter is a common problem regardless of the house condition. And low humidity prevention strategy is necessary for most of the houses in winter. ²⁾ Then, to estimate the quantitative effects of various low humidity prevention strategies, we performed experiments both in the laboratory scale house and the occupied houses. As the result, we quantitatively estimated the humidity rise due to each low humidity prevention strategies such as Total heat exchanger, Foliage plant, Drying laundry, Humidifier, Opening bathtub, and Humidity controlling material.