Design of 2-hour fireproof wooden beam protected by wood-based fire protection barrier is studied. The lightness of the structure, one of the most important features of the wooden construction superior to the reinforced concrete and steel constructions, becomes more significant as the buildings become taller. The study aims at minimizing the total weight of the fire protection barrier, which is composed of the Phosphorus fire-retardant treated wood layer and, if necessary, the surface sacrificial layer and is notably heavier than the load-bearing part, assuming Japanese cedar as the material. Through review of previous studies, it has been expected that the sacrificial layer with the universal optimum thickness for Japanese cedar(25mm) can substitute for the 1.5 times heavier treated wood of the same thickness and the bottom and the lower corners of the beam may need thicker barriers than the vertical sides for possible dropping of the sacrificial layer during fire heating and the increase of the relative heating surface especially at the corners.

 The following three series of furnace tests are conducted to clarify the necessary performance and thickness of the treated wood for the barrier on the vertical sides, the bottom and the lower corners.

 Test I) Bench-scale test on specimens reproducing the barriers of vertical side part in order to explore the suitable treatment and thickness of the treated wood barrier for the 2-hour fireproof wooden beam

 Test II) Unloaded full-scale test on an entire beam cross section to verify carbonization of the bottom and lower corners

 Test III) Bench-scale test on specimens reproducing a lower corner with different treated layer thicknesses

 Test I has revealed the followings:

 ①Whether the wood within 25mm from the surface is treated or not, there is no influence for the achievement of the 2-hour fireproof performance. Use of 25mm thick of sacrificial layer is effective to reduce the weight of the total assembly.

 ②The target amount of the fire-retardant agent of 120kg/m³ is found to be not enough to suppress glowing combustion against the 2-hour ISO834 standard fire heating, while sufficient performance is demonstrated for 180kg/m³. The test result suggests the effectiveness of the fire-retardant treatment as the barrier for 2-hour fireproof performance would reach the upper limit at around 150kg/m³.

 Test II has revealed that:

 ①Using an extra lamina(25mm thick) treated wood for the bottom is effective to prevent the dropping of the charred protection layers during the fire heating and secure the 2-hour fireproof performance.

 ②The lower corners can be critical for the achievement of any design fireproof performance, due to the largest relative heating surface area during the fire heating and the reduction of the heat exchange performance after the heating by the dropping of the edge surfaces. Design of the lower corners is found to be the key for the fireproof performance of wood-based fire protection layers.

 The result of the Test III suggests the following specification as the minimum weight 2-hour fireproof wooden beam with totally wood-based fire protection: i) 25mm thick sacrificial wood, ii) 75mm thick treated wood on the vertical sides and 100mm thick treated wood on the bottom as fire barriers, and iii) target amount of Phosphorus fire retardant agent of 180kg/m³.

 Having put forth the hypothesis that time perspectives affect opinions on housing and family life, the current study was conducted in order to determine the validity of that hypothesis in married or divorced individuals who had moved. A multi-group analysis by sex was used to develop a causal model that yielded the following findings:

 ・ When moving, looking to the future - thinking about one’s “living situation”→”future living space”→a home’s “basic specifications” - increased one’s satisfaction with one’s new housing. Looking to the past - i.e. thinking abour one’s “living situation”→”resuming life” - increased women’s satisfaction with new housing, while “basic specifications” increased men’s satisfaction.

 ・ “A couple’s dissatisfaction with the residence they were moving in to” had a negative effect on the happiness of both men and women.

 ・ An unbalanced family life encouraged divorce and reduced happiness while thinking about a new home’s “basic specifications” increased happiness.

 Views on life and issues with them are described below.

 Thinking about “living situations” involved 2 aspects: “routine activities,” i.e. the flow and efficiency of household chores, and “living conditions,” i.e. noise, dust, and odors. In other words, this means thinking about everyday life (in the near future) soon after moving. This approach touched on questions related to household chores, but it did not affect the “balance with family life,” so it was not reflected in actual life. Thus, this approach needs to be analyzed anew in terms of a family’s help with and views on household chores.

 Thinking about “future living space” had but indirect effect on opinions on housing.

 Thinking about “resuming life” reduced thoughts of divorce, albeit only slightly. Thus, a continuity of life from one’s previous residence helped to limit thoughts of divorce.

 Thinking about “basic specifications” had a major direct effect on opinions on housing. Couples were asked about aspects such as rent, the purchase price of a home, its quality and size, etc. led to their final housing choice.

 In short, thoughts about “living situations [the immediate future]” affected thoughts about one’s “future living space [the future]” and “resuming life [the past]” and ultimately affected thoughts about “basic specifications.”

 This time perspective on life affected one’s opinions on housing.

 In more concrete language, these perspectives presage future changes, i.e. “Is one satisfied with a residence; can a home make one happy?” [effectiveness] and “Can a balance with family life be achieved?” Envisioning those changes should prepare a couple for family life.

 Plans are to analyze the relationship between whether or not a couple has children and the effects of changes in a spouse’s work patterns and housing from the perspective of work-life balance in a subsequent study.

 In Japan, measurement of the floor impact sound using standard heavy impact sources is stated in JIS A 1418-2:2019, and measurement of the reduction level of the floor impact sound using standard heavy impact sources is stated in JIS A 1440-2:2007. In both standards specifies the tire as a standard heavy impact source (1) and the rubber ball as a standard heavy impact source (2).

 Even though both tire and rubber ball are standardized in JIS, the use of the rubber ball is limited. For example, the ball can be used in AIJES-S001-2008. But the tire can be used in Housing Performance Indication System, Promotion of Housing Quality Assurance, and the sound insulation performance standards of the Architectural Institute of Japan, etc. Considering this situation, it would be preferable to use both tire and ball than to use only one of them. However, the translation of the measurement done by the tire to the rubber ball or vice versa is investigated, but only in the low-frequency range and yet solved.

 Hence, this paper investigated the use of a machine learning algorithm as a solution to the translation between two different standard heavy impact source measurements. The Random forest regression model was investigated as a prediction approach for the floor impact sound and the floor impact sound reduction level. At present, the sample is biased toward the data of the wall-type structural test chamber at the Building Research Institute, hence, the verification is limited. However, the outcome suggests that the maximum difference between measured and predicted floor impact sound level (L_Fmax) was within 2.3 dB for tire source and 2.5 dB for rubber ball source. In terms of the floor impact sound reduction level (ΔL_Fmax), it was within 3.9 dB for tire source and 3.6 dB for rubber ball source. For both L_Fmax and ΔL_Fmax, the variance by inter quarter range shows a good agreement between measured and predicted values. Hence, the paper showed by using random forest regressor, it is possible to translate the measurement done by the tire to the rubber ball or vice versa by changing the feature of the excitation source from the tire to the rubber ball.

 The purpose of this study is to provide a comfortable lighting environment corresponding to age and life activities. The required illuminance and correlated color temperature (CCT) differs by age. In this paper, we think that the main cause of this is a change in feeling of brightness and color with aging and that there is no major difference in an allowable brightness and color for a life activity by age. We examine this based on the result of the subjective evaluation experiment. Eight people are included in each age group. The experimental range of illuminance is 30–950 lx and that of CCT is 2900–5200K. We take up five life activities in daily life (reading newspapers, eating, getting-together, relaxing, and sleeping).

 The main findings are as follows:

 1) When they can permit a color, the relations between brightness and its acceptable level is different between life activities. However, they are approximately matched between age groups in every life activity.

 2) When they can permit a brightness, the relations between color and its acceptable level is different between life activities. However, for the elderly, a change of the acceptance level is small due to an apparent of color in each life activity.

 3) There is a common range of brightness and apparent color between the young and the elderly which are evaluated acceptable or almost-acceptable. Brightness is required for activities with a high degree of visual work, and color is required for activities with a high degree of relaxation. Furthermore, we grasp a difference between age groups regarding interaction of illuminance and correlated color temperature for inducing a feeling of brightness and color.

 4) As for a brightness, in the case of low illuminance, the lower CCT, the brighter the young feel. On the other hand, in the case of high illuminance, the lower CCT, the darker they feel. For the elderly, the lower CCT, the brighter they feel regardless of illuminance.

 5) As for an apparent color, the lower illuminance, the more they feel colored regardless of CCT. For the elderly, in contrary to the young, the higher illuminance is, the more they feel colored, but there is no clear difference.

 In this paper, we clarify that there is an almost-allowable brightness and color for both age groups in each activity. This enables planning of illuminance and CCT suitable for life activities by setting age as an explanatory variable for a general index of the sensitivity of eyes and clarifying a relationship between illuminance and CCT, and a feeling of brightness and color, quantitatively in future.

 In our research on the perception of illumination change, we conducted an experiment that incorporated as factors a warning signal before a change of lighting and various lighting positions. We analyzed the perceptual characteristics of each factor under situations that are similar to actual work spaces, and also examined the dimming method of variable lighting that is comfortable for the employees’ working environment by analyzing the results together with the findings of previous research.

 In Experiment 1, general lights were installed at three locations directly above each seat, and the lighting was continuously dimmed with a dimmer. In Experiment 2, lighting positions were added that could be moved obliquely or laterally in order to examine the effect in situations where the positional relationships between the worker and the lighting were similar to those of actual working spaces. In addition, LED lamps were installed under each general light that gave a warning signal about 10 seconds before a lighting change. This process was explained to the subjects at the start of the experiment. The subjects were asked to do office work combining writing and visual-display terminal work, and to answer a questionnaire each time they noticed a change in lighting brightness while working. They answered the questionnaire about how the brightness of the interior space and desk surface changed by selecting one of three choices (brighter / darker / no change). They were also asked if they were concerned about the change (their degree of concern about the brightness change) using the seven-step semantic differential method.

 From the experiment results, the following findings were obtained.

 1) Regarding warning before a change of lighting, it was found that the perception rate and degree of concern about the brightness change were low for the lighting of the seat on the separate work island. The result suggests the possibility that in actual offices where worker’s sitting down and standing up is accompanied by changes in lighting, the effects of a change in brightness at a location away from the worker may be less than the perceived rate and degree of concern obtained in previous studies.

 2) It has been shown that not only a change in illuminance but also the magnitude of the change in the subject's visual field affects the perception. In addition, it has been found that the change is more noticeable at the time of increasing the lighting than at the time of dimming the lighting.

 3) Based on the related research results, including this research, it has been found that the degree of concern of a worker about a change in brightness of fluctuating lighting is correlated with the amount of change of illuminance (the amount of change in illuminance per unit time, lx/s), and when the starting illuminance is 750 lx, a change is more likely to be noticed at a change amount of 20 lx/s or more.

 LED has become one of the most popular light source for general lighting. Hereafter, it is supposed that lighting design assuming dimming and toning control of LED lighting will be usual from the viewpoints of energy saving and the occupants’ health and visual comfort. Currently commercial dimming and toning controllable type of LED luminaire is usually composed of multiple different colours of LED and it can realize a variety of luminous colour by combining the levels of the output of each colour LED. However, the chromaticity coordinates of toning controllable LED luminaires tend to be located on the negative side of the Planckian locus. Some present studies have identified that the difference in d_uv effects on colour naturalness, colour preference, brightness and etc. Correlated colour temperature of the luminaire can be expressed as the same in the cases with the chromaticity distance from Planckian locus, d_uv within ±0.02 according to JIS Z 8725: 2015. However, it is identified that the threshold of d_uv for the perception of the difference in luminous colour is much smaller than ±0.02. Light with the same correlated colour temperature but with different d_uv may give different impression from as expected.

 In this study, subjective experiment was conducted to identify the effect of the chromaticity difference from Planckian locus d_uv of LED lighting on the spatial brightness with consideration of the interior wall material. Fifteen university age students (ten males and five females, 21.4 years old in average) participated in the experiments as the subjects. Two cube models with the same size of 600 mm each in width, in depth and in height were prepared for the experiment. The interior wall surface of the model was finished with 5 different types of wall paper with the reflectance ranging from 0.14 to 0.78. Each model was illuminated by the LED lighting through the sheet of translucent paper on the hole settled at the centre of the ceiling. Six different lighting condition, two levels of floor illuminance and three different d_uv, each for two different correlated colour temperature, 2800K and 5000K, were tested. The floor illuminance was set using ND filter and d_uv was set using colour filter. The subjects evaluated all 60 conditions.

 The experiment was conducted in two methods- comparison method and absolute method. The first one was that the subjects compared the spatial brightness of the test model with that of the reference model with the condition of 300 lx in the floor illuminance and 5000K (d_uv≒0) in the correlated colour temperature. The second one was that the subjects evaluated the spatial brightness of the test model using VAS (Visual Analog Scale).

 The results showed that d_uv showed different effects on spatial brightness depending on the type of interior wall material. For the woodgrain wallpaper with the reflectance under 20%, the subjects sensed the spatial brightness significantly darker as d_uv became higher in the cases with 2800K of the correlated colour temperature. It was also identified that in the cases with 5000K of the correlated colour temperature, they sensed the spatial brightness significantly darker with d_uv>0 and d_uv<0 than with d_uv≒0.

 The indoor temperature, humidity and air environment at children's facilities such as kindergartens, nursery schools, and child institutions need to be carefully adjusted in order to keep children healthy. Especially during the winter, it is important to prevent the spread of infectious diseases including influenza. This study aims to evaluate the actual conditions of indoor temperature, humidity, and CO₂ concentration, and the environmental control and influenza measures used in children's facilities during winter. We conducted a questionnaire survey and a field survey of kindergartens and nursery schools, and child institutions in the southern Tohoku region. The purpose of the questionnaire survey was to estimate the availability of installed air purifiers, humidifiers, and other indoor environmental adjustment methods. The purpose of the field survey was to evaluate the air environment, actual temperature, and humidity, of children's facilities during winter, and to clarify the factors that influence them.

 The survey targets were children's facilities located in the Miyagi and Yamagata prefectures in the southern Tohoku region. The questionnaire survey was conducted from October to November 2017. The questionnaire was distributed to 538 facilities, and the effective recovery rate was 50.6%. The field surveys were conducted in three or four childcare rooms at each of eight facilities from January to February 2018. In each facility, the indoor temperature and relative humidity in each childcare room were measured. Additionally, at one facility, the CO₂ concentration was measured in a room for five years old.

 The major findings are as follows:

 1) The installation rate and the perfection rate of air purifiers and humidifiers in the southern Tohoku region were the highest, and they were superior to the rates in the Tokai and Hokuriku regions. Moreover, the influenza countermeasures used in southern Tohoku tend to emphasize humidification and is significantly different from the approach used in the Tokai and Hokuriku regions.

 2) The temperature in the childcare room was approximately 15.9-23.7 °C, the relative humidity was 23.5-52.3 % and the absolute humidity was 3.7-7.3 g/kg’.

 3) Air changes per hour in the southern Tohoku region was 2.0, which was about the intermediate level compared to the Gifu and Hokuriku regions. In addition, it was suggested that the indoor CO₂ concentration may exceed 1500ppm if the number of children exceeds 0.2 person/m³.

 4) Children's facilities in the southern Tohoku region tend to emphasize on humidification, against the background of the lowest absolute humidity and have been able to keep indoor absolute humidity higher than that in the Gifu area included in the Tokai region.

 5) Children's facilities that emphasize humidification tend to have higher indoor absolute humidity on the day of the spread of infection than Children's facilities that emphasize ventilation. Furthermore, CO₂ concentration also tended to be high. Therefore, there is a possibility that the ventilation volume is insufficient, and it is also necessary to consider the air cleanliness.

 In this study, it is assumed that those who cannot return home will stay in the underground mall space for about one night at the time of disaster. Therefore, in order to understand the stay environment, we measured the thermal environment without the air-conditioning, and conducted the subject experiment on the actual state of sleep and the change of fatigue assuming night stay in the thermal environment. The obtained findings are shown below.

 1) During the daytime in summer, air conditioning was controlled at around 27 °C. During non-air conditioning at night, the temperature was almost the same as the outside air temperature. It was confirmed that the average temperature at night increased by 0.65 to 1.79 °C compared to the daytime. In intermediate season, there was no air conditioning throughout the day and night, but there was no significant temperature change at around 20 °C. During the daytime in winter, when the outside air temperature was hovering around 5 to 7°C, the temperature was hovering around 15 to 18°C, except for the area around the entrance/exit stairs. On the other hand, the temperature at measurement point 2 was only 7 to 9 °C even under air-conditioned conditions, indicating that there was a large temperature difference even within the underground mall.

 2) From the results of wind velocity measurements, the underground mall space closed with shutters with gaps is significantly lower than the surrounding wind velocity above the ground. It had dropped to 34.2 % in intermediate season and 11.5% in winter. However, it was confirmed that there was a time period when the wind velocity was high enough to feel the airflow physically, and it was confirmed that the influence of the airflow on the thermal sensation could not be ignored.

 3) According to the PMV evaluation during the sleep experiment, the average PMV in summer was 0.75 in the sleeping state and 1.34 in the sitting state, indicating that it was slightly warm even when it was at rest. In intermediate season, the patient was in a comfortable state with a sleep state of 0.01 and a sitting position of 0.75. In winter, it was －1.72 in the sleeping state and －0.39 in the sitting position, so it was confirmed that the sleeping state was cold.

 4) As a result of studying sleep quality and fatigue recovery status, the Sleep onset latency is short and the Latency to persistent sleep is long in summer. On the other hand, in winter, it is difficult to fall asleep deeply, the Wake episodes are long and the number of times of Long wake episodes are high, so when the person goes into sleep and the metabolism falls, the person wakes up immediately because he feels cold. Regarding fatigue recovery, the correlation with the longest sleep episode was the highest, with a correlation coefficient of 0.52, but there was no significant difference between the seasons.

 5) Based on the measured results, it was shown that the measures to reduce the feeling of warm and cold during temporary stay in summer and winter were to add airflow of 0.6 m/s or more with a fan or other device in summer and to maintain a temperature of 20°C or more with a portable heater or other device in winter.

 Around 1965, droughts began to occur frequently, and rainwater was needed to toilet flushing water. In recent years, the use of rain water has been regarded as important for securing water during disasters, and has become popular.

 The purpose and effect o f the introduction of rainwater use facilities to buildings include effective use of water resources, suppression of outflow to rivers and sewers, reduction of environmental burden, emergency response, water saving, etc.

 The paper listed the quality of the initial rain water and the effect of make -up supply water on the carbon dioxide emission.

 (1)Initial rainwater removal is important to maintain the water quality of rainwater utilization facilities. It is recommended to remove the initial precipitation up to 1 mm from the viewpoint of turbidity and electrical conductivity, and up to 2 mm for higher quality precipitation. It was clarified that the carbon dioxide emission per water volume accompanying the make -up water supplied from the water supply facility varies greatly depending on each prefecture.

 (2)It was revealed that the carbon dioxide emission per water volume by water supply facility is 3.4 times larger than the carbon dioxide emission per water volume related to rainwater utilization facilities. Carbon dioxide emission per water volume affects buildings with relatively low water supply substitution rate and buildings with relatively high water supply substitution rate, but also water supply substitution rate . Therefore, it was pointed out that it is necessary to evaluate the water supply substitution rate as well. It is necessary for rainwater utilization facilities to evaluate not only the carbon dioxide emissions related to transfer and disinfection of rainwater collection but also the carbon dioxide emissions related to make-up water.

 The paper was able to propose the amount of water to be removed from the initial rain water, and a way of thinking about the amount of make-up water supply that greatly affects carbon dioxide emissions . However, there are other methods for evaluating rain water utilization facilities, so a comprehensive evaluation is required.

 This paper describes the results of a couple of field measurements and an exergy analysis on the traditional radiant heating system, “grounded Kang” in the northeast region of China. Biomass is one of renewable energies and its utilisation has been challenged all over the world. Exergy analysis can provide us with deep insight about how local or global resources should be consumed, which subsystem and how total system should be designed in order to avoid unnecessary exergy consumption. The authors consider space heating with Kang can be a reference example studying relationship between daily life with biomass and exergy consumption. From such a point of view, the purpose of this paper is to grasp the detailed heating effect of grounded Kang as a radiant heating system and its differences in the characteristics of exergy-consumption process from other biomass-based heating systems.

 The result obtained from this study are followings. 1) Both the room air temperature and the MRT measured were kept within the range form 20 oC to 26 oC. Thermal discomfort was avoided by this traditional heating measure. 2) The amount of primary exergy input for grouned the Kang is 12.8 GJ/week and that for the elevated Kang is 4.6 GJ/week. This difference in primary exergy input between the Kang and the elevated Kang, 8.2GJ/week (=12.8-4.6) means the advances of combustion efficiency and thermal storage effect in the elevated Kang. 3) Exergy efficiency of the grounded Kang based on primary input is 0.034 and the smallest among the three biomass based space heating systems. There is some differences in exergy efficiency between the elevated Kang and air conditioner driven by biomass power generation: the elevated Kang 0.092 and air conditioner from 0.107 to 0.151 corresponding to power generation efficiency from 23 % and rice straw transport distance 1000km to 28 % and rice straw transport distance 100km. 4) PMVs are from 0 to +0.5 in three heating systems, but the MRT in case of air conditioner is from 3oC to 7 oC lower than the room air temperature, because air conditioners do not have radiant heating effect. As a result, there is possibility that cold draft may occur from near windows more frequently in case of air conditioner than the other two space heating systems.

 In case that rice straw transport distance is 100km or less, air conditioner driven by biomass power generation is more efficient than the elevated Kang, if considering the fact that farmers tend to avoid selling their rice straw to an electric power company, residents should use the elevated Kang whose energy performance is superior to the grounded Kang and the briquette of rice straw

 This study analyzed construction Embodied Greenhouse gas emissions (EG) using input-output tables and CO₂ emission data obtained from 40 countries. The analysis used input-output tables of 35 sectors, provided in the World Input-Output Database (WIOD). The analysis revealed the following;

 1) The intensities of the 35 sectors in the 40 countries and the CO₂ emissions by sector were calculated. It was verified that the construction sector accounted for the largest share (20%).

 2) We developed a diagram showing the relationship between the CO₂ emission ratio and the construction EG ratio for each of the countries, and demonstrated the impact of construction EG (Fig. 1). The larger the square area of a country, the larger is the magnitude of the construction EG. Thus, it was shown that China exerts the highest impact.

 3) China has the highest construction EG share (36%), followed by India (25%), Indonesia (21%), and Turkey (14%). The BRICS countries Brazil (14%) and Russia (10%) also have relatively large values.

 4) The smaller the GNI per capita, the higher is the construction EG share. It can be stated that the construction EG of developing countries tends to be large because the investment in the construction of roads and buildings is generally undertaken at the developmental stage.

 5) An analysis of the composition of the sectors that have invested in construction in 10 countries shows that three sectors (11:Other Non-Metallic Mineral, 12:Basic Metals and Fabricated Metal, 17:Electricity, Gas and Water Supply) exerted a large impact on the construction sector. These sectors are related mainly to cement production, steel production and energy supply.

 6) Cement manufacturing and construction EG are highly correlated. The construction EG is approximately three times of the CO₂ emissions from cement production.

 7) The relationship of the total CO₂ emissions with the construction EG and with the CO₂ emissions from cement production was analyzed for Japan, the United States, China, and India for the period 1995–2009. In China and India, the total CO₂ emissions, construction EG, and cement are increasing each year because they are still developing. Meanwhile, the US, which is a developed country, has negligible fluctuation. In the developing countries, the construction EG tends to increase each year.

 8) The variation in the construction EG share tends to increase for China and India. This can be said to be a characteristic of developing countries and is similar to the above case.

 It is evident from the above-mentioned discussion that the reduction of construction EG in developing countries is important for global CO₂ reduction. This is because the construction EG will increases when a developing country transform into a developed country. To reduce construction EG, it is effective to develop and provide technologies that can achieve low carbonization in cement production, steel production, and energy supply source. In addition, in developing countries where construction would be carried out, investment in construction will continue for a certain period. However, it is considered that the construction of buildings that consider the life to the extent feasible at that time would contribute to the reduction of construction EG in the future.

 The goal of this study is to propose combinations of equipment, including photovoltaic (PV) power generation and storage battery (BT) charging, in a net zero energy house (ZEH) that considers sheltering at home during power outages. To validate the resilience performance of houses in various conditions compared to a ZEH house, the self-sufficient rate during power outages was calculated based on PV capacity, BT capacity, and insulation performance. Assuming that the power supply is limited, such as in the case of small BT capacity and bad weather, an occupant behavior was proposed to make efficient use of the limited power supply and evaluated based on the self-sufficient rate and thermal environment. Moreover, the economic efficiency of the ZEH was calculated to prove the feasibility of the study.

 The following observations are reported in this article:

 1) The thermal insulation was effective in reducing the electricity consumption for heating and cooling, and the reduction was particularly pronounced in the winter. The impact of increased PV capacity on the increase in the self-sufficient rate is small compared to the changes in thermal insulation and BT capacity. In addition, with a UAvalue which is thermal transmittance of 0.46 W/(m²・K), the installation of BT results in an 80% self-sufficient rate. Notably, the self-sufficient rate increases proportional to the increase in BT capacity. Under conditions of BT capacity of 6.2 kWh or more, 100% self-sufficient rate was achieved. Furthermore, by setting the BT residual rate for emergency, the self-sufficient rate is further increased, and the resilience of the occupants in the ZEH is increased in cases of unexpected power outages.

 2) Even in conditions where the BT capacity is less than 5.6 kWh, a BT is not installed, or there is low solar radiation, occupant behavior, such as reducing the air conditioning range and limiting the home appliances’ time of use, can help maintain thermal comfort without compromising health. When a BT is not installed, the starting power of the air conditioner in winter exceeds the maximum power output of the self-support circuit, making it difficult to use the air conditioner. However, it has been shown that the air conditioner can be used both in the summer and winter by installing a BT. Therefore, in a house with a UA value of 0.46 W/(m²・K), it is noted that the installation of a BT can be expected to serve to further prepare for power outages, even when the occupant behavior is devised during power outages.

 3) As the capacity of the equipment increases, the increase in the equipment installation cost is greater than the decrease in the annual electricity bills. It is shown that the annual cost per unit per year increases. Moreover, as the BT residual rate for emergency increases, the self-sufficient rate on the first day of the power outage increases, but the annual electricity bill increases as well.