Various indices have been proposed to quantify the modal influence in sound field of a small room. However, no measurable index has been established for actual rooms. This study focuses on the frequency-domain coefficient of variation (FCV) as a potential index for quantifying modal influence. Nevertheless, the specific room acoustic parameters influencing the FCV remain unclear. Therefore, the paper aims to formulate the FCV based on two parameters: “modal density” and “energy variation” of the modes. Additionally, the study compares the FCV and modal density. As a result, a high correlation was found between the FCV and modal density.

We analysed the regional characteristics of thermal discomfort in summer in three schools in Japan, with respect to cognitive temperature. We conducted an experiment involving the participation of elementary school students in Sapporo, Tokyo, and Kumamoto. The results indicated that if the room temperature was not checked, the cognitive temperature could be quantified based on the outdoor temperature, and if the room temperature was checked, the cognitive temperature could be quantified based on the room temperature. The cognitive temperature voted by half of the school children as “hot and uncomfortable” was the lowest in Sapporo and the highest in Kumamoto.

In order to study ZEH incorporating passive design methods that take into account the balance between summer and winter heating and cooling loads in detached houses with high annual CO2 emissions, this study analyzes the evaluation of passive design in the design stage and measured data in actual dwellings in passive houses, We will clarify the relationship between passive design, annual heating/cooling load, and primary energy consumption.

This study aims to examine the impact of retrofitting an existing low-rise apartment to meet ZEH standards in terms of energy conservation, thermal comfort, and resilience. The retrofitting includes upgrading the insulation from 1980s standards to ZEH standards, modifying the floor plan for better usability of the room, and introducing a photovoltaic (PV) system and battery storage (BT). As a result, the retrofitting contributed to both energy conservation and improved thermal comfort. Furthermore, the introduction of PV and BT supported a stable energy supply during normal conditions and ensured a minimally healthy living environment during power outages.