Experimental Evaluation of the Moisture Buffering Effect of Hygrothermal Material

Residential buildings newly constructed in Japan are well insulated and airtight for energy conservation. However, the indoor environment of these houses can suffer from high humidity in the summer and low humidity in the winter. In order to mitigate this problem, hygrothermal materials are installed in some Japanese houses. The test method for small samples of hygrothermal material is prescribed in the Japanese Industrial Standards (JIS). However, the moisture buffering effect of the hygrothermal materials adopted in actual houses is unclear. The purpose of this study was to clarify the effect of hygrothermal material on indoor moisture control. A series of experiments was carried out in two identical rooms. In the room installed with hygrothermal material, variations in relative humidity were controlled and compared with the room without hygrothermal material. This material demonstrated good performance for moisture buffering effect in an actual-scale room.