We proposed formulas to estimate the medical costs from the thermal environment in houses. Using these formulas, we examined the most economical thermal insulation performance, taking into consideration insulation costs, heating and cooling costs, and medical costs. The UA value of a house having this most economical insulation performance is 0.4 to 0.5 W/m2K for a floor-insulation house, and 0.36 to 0.4 W/m2K for a foundation-insulation house. We found that by considering not only heating and cooling costs but also medical costs, the cost recovery period for the improvement in the thermal insulation performance was significantly shortened.

It takes many years to recover the initial investment cost for installing housing insulation through savings from energy reduction (Energy Benefit:EB), since construction cost is very high in Japan. This long payback time is the major barrier to the promotion of well-insulated houses. However, it has been found that if Non-Energy Benefits (NEB) of well insulated houses, such as improvement in personal health, reduction of medical expenses and decline in absences from work are all taken into account, the time required to recover the initial investment cost would change from 29 to 16 years. Therefore recognition of NEB is expected to encourage residents to invest in residential thermal insulation. NEB of well-insulated houses is thus evaluated regarding human health in this study.

In order to save energy consumption for air-conditioning of buildings throughout those lifecycle, thermal performance of insulation materials applied in buildings should be kept in required value. On the other hand, there are many factors of ageing of insulation materials such as ambient temperature, vibration and moisture etc. In the previous paper, main factors of thermal performance change were discussed and several experimental results were shown. This paper examines the influences of moisture on thermal performance of various insulations based on three kinds of experiment. In first experiment, the relationship between equilibrium moisture content and thermal conductivity of fiber insulations is obtained. Second experiment is on the influence of gaseous moisture on fiber insulations and the results show that the dimension change of fiber insulations is small even in very humid condition. Third experiment is on the reversibility of thermal conductivity after the internal dew condensation process and the dry process, and the results show that many insulation materials have reversibility except for several plastic insulation foams.

Thermal performance of insulation materials decreases with the passage of time. Such ageing of insulations should be considered in the design stage of buildings to keep insulation performance within the required one throughout the lifecycle of buildings. Firstly this paper focused various factors that affect performances of insulations. The main factors for fiber insulations are moisture vibration and microbe. The main factor for plastic insulation foams is ambient temperature that accelerates the diffusion of blowing agent. Secondly real performances of sold new insulations and scraped old ones were measured and compared the required value by Japanese standard. Performances of some insulations were lower than standard values and performance change was detected. Finally this paper discussed the influence of vibration on performance for fiber insulations based on the experimental data. The changes of insulation depth and thermal resistances were observed after the vibration test.

There are two points of view for the prevention design of moisture problem in the building insulated envelope. One is the strictly prevention of high moisture condition in the insulated wall cavity. The other one is the permission of short-term high moisture condition, condensation and high moisture content of the wooden material as long as keeping physical durability. If the later standpoint were chosen, the insulated envelope design of every variety for Japan would be possible. Nevertheless, there are no criteria to estimate the damage of physical durability of wood by the biological factors related high moisture condition. In the previous paper, we reported about the concept of the prevention design of moisture problem in the building insulated envelope and the relationships between water content and decay various woods under hygrothermal steady conditions. In this paper, the relationships between water content and decay of various woods under two kinds of hygrothermal transient conditions are shown.

There are two points of view for the prevention design of moisture problem in the building insulated envelope. One is the strictly prevention of high moisture condition in the insulated wall cavity. The other one is the permission of short-term high moisture condition, condensation and high moisture content of the wooden material as long as keeping physical durability. If the later standpoint were chosen, the insulated envelope design of every variety for Japan would be possible. Nevertheless, there are no criteria to estimate the damage of physical durability of wood by the biological factors related high moisture condition. The points of this paper are as follows 1) The importance of estimation damage of woods by the moisture problems is describes. 2) 2 case of hygrothermal steady state experiments were done to get basic acknowledge of woods damage by biological factors considering term, water content, temperature and humidity, physical durability.

We present a heating system with thermal storage using a heat pump which supplies heat to the thermal storage installed in a crawl space of a residential house insulated at the foundation walls. We used latent thermal storage materials. This system can charge heat by using cheap nighttime electricity and discharge the stored heat at daytime. We showed equations to determine the air volumes of the heat pump and the ventilator, and equations to determine the phase transition temperature and the amount of the latent thermal storage materials to keep the room setting temperature. We constructed a computer simulation program of this heating system and confirmed the validity of these equations.

We present a heating system with thermal storage using a heat pump which supplies heat to the thermal storage installed in a crawl space of a residential house insulated at the foundation walls. We used sensible thermal storage materials. This system can charge heat by using cheap nighttime electricity and discharge the stored heat at daytime. It is revealed by experimental studies that thermal behavior of the room is greatly influenced by the heat capacity of the thermal storage. We constructed a computer simulation program of this heating system and showed the ratio of the stored heat for generated heat by the heat pump with the volume of the thermal storage materials. We showed the way to determine the volume of the thermal storage materials and the capacity of the heat pump.

'Crawl-space heating' is a heating system using the crawl space as a duct for heat transport from a heat pump. The purpose of this study is to grasp the convective heat-transfer coefficient at the slab-concrete surface and the floor-under surface, under the condition of crawl-space heating. When the crawl-space heating is operated, the air velocity in the crawl space is generally 0.05-0.20m/s and the heat transfer is caused by both the forced convection and the natural convection. We measure the convective heat-transfer coefficient by the wind tunnel test. It is revealed that the convective heat-transfer coefficient at the slab-concrete surface is about 1.0-4.0W/m 2K and that at the floor-under surface is about 6.0-10.0 W/m 2K.

In this paper, we present a heating system with thermal storage using a heat pump which supplies heat to the thermal storage equipment installed in thecrawl space of residential house insulated at the foundation walls. This system can charge heat by using cheap nighttime electricity and discharge the stored heat at daytime. The thermal performance of the heating system and the effects of various factors on it are analyzed through simulation on the premise that a heat pump which has generally spread is used. The main results are as follows: (1) It is possible to control the system efficiently adjusting the lifestyle by change the start time of the operation of the ventilator connected to the thermal storage equipment to discharge the stored heat. (2) Using the latent thermal storage materials, the change of the room temperature can be made moderate.

It is well known that humidity influences cooling load, thermal comfort and durability of buildings and various items in them. Many works on prediction of humidity variation in a room have regarded the humidity as unique in a space. However, it does depend on air movement. This paper describes calculations of minute moisture distributions in a room affected by moisture buffering of porous walls. The air velocity distribution is calculated by CFD using two different turbulence models. Then the heat and vapor transient transport in walls and space is calculated. This shows that moisture distribution is not negligible. The difference between the two turbulence models is also determined.

In this paper, we report the experimental studies which were carried out in an experimental house with thermal insulation for its foundation walls, concerning (a) the indoor thermal environment and (b) the heat flow in the crawl space to the ground and to the floor, under the condition of crawl space heating. The main results which we obtained are as follows: 1. The temperature in the room ranges from 18 to 21℃, and that of the floor surface becomes over 23℃. 2. When a fan is put in operation in order to control a current of air in the crawl space, the flow of the heat towards the floor increases, but that towards the ground also increases out of the warm air blowing out zone. 3. It is suggested that most of the heat to the ground is brought by radiation from the lining of the floor.

We found many houses have condensation in the crawl space in summer. These houses have enough openings on the foundation to ventilate and vapor retarder at the ground surface for the recommend in the building code. The temperature and humidity in the crawl space have great influences to durability of the house. We made clear the annual variations of hygro-thermal environment of the crawl space by the field measurements and numerical analysis. We monitored the temperature and humidity variations of 36 houses in Japan for 2 years. The numerical calculations based on the vertical one dimension heat transfer model represented the monitored results. The results show the houses in Japan normally have condensation in crawl space in summer. The condensation term is from one week to one month. The daily average of crawl space's vapor pressure is nearly equal to that of the outdoors. The difference of 2 years results is so great that we think the main factor is outdoor condition. The thermal resistance of the floor and moisture of the ground do not have great effect on the crawl space humidity.

Contamination of thermophilic fungi (grown at 40 C) in house dust was studied. The number of A. fumigatus in house dust was affected by temperature and humidity in the climate. Moreover, the number of thermophilic fungi in Okinawa with subtropical climate was larger than that in Osaka or Kochi Prefecture. Thus, the higher humidity as well as temperature in the outdoor environment seems to affect the thermophilic fungal contamination indoors. Global warming translation is thought to bring apparently a more suitable environment for thermophilic fungi. i.e. A. fumigatus.

We conducted questionnaire survey and field measurements on 6 cities in China. Results of the questionnaire survey suggested the association between mold and chemical pollution and children’s allergic diseases. The results also showed that the prevalence of allergic diseases in southern three cities was higher than that in northern three cities. On the other hand, results of the field measurements showed that there was no difference in air concentrations of fungus and chemical substances between the groups with and without allergic diseases. However, concentrations of TVOC and PM2.5 were higher in southern cities than in northern cities, and it is not contradictory to the prevalence of allergic diseases. Measured indoor temperature and humidity suggested that Chinese houses were little improved on thermal insulation but reduced air change rate in this decade. We proposed the minimum thermal resistance of houses for preventing winter dew condensation from the aspect of mold prevention.

The purpose of this research is to clarify the optimal design method and lifestyle for solving the problem of a damp building. Therefore, nationwide survey about the damp building was conducted, and the relationship between living environment and a resident's health was clarified statistically. The use effect of high humidity environmental relief technology, such as hygroscopic material was evaluated using the experiment and the simulation.

Research results are composed of the following two terms. 1. Experiments on wood decay Principal members of the investigators had visited famous laboratories in Canada and Germany and surveyed the state-of-the art researches about wood decay. On basis of these surveys, Hygro-thermal simulations were performed to predict temperature and humidity inside insulated wood-frame envelopes. Experimental conditions in temperature and humidity were defined using these simulation results. Long term experiments on wood decay had been conducted under those conditions. In these experiments, periodical observation of wood specimens regarding mould, activity of rot bacteria, color change and deformation was carried out, and measurements were also done in weight and dimension. In addition, mechanical strength, such as longitudinal compressive strength, was measured every month after drying out wood specimens 2. Formulation of biological damage function on wood products By analyzing the above experimental results, knowledge about wood decay was systematized. New biological damage function was formulated according to that knowledge and is also a goal of this project. In the damage function, damage is expressed with durability deterioration. Furthermore the durability deterioration is indicated by degree of decay. Finally degree of decay is formulated with moisture content, time equivalent to hypha growth and so forth, which is an important result of the project. Consequently the damage function enables engineers and designers to predict degree of decay and durability deterioration in wood products numerically, if they will conduct hygro-thermal simulation in insulated envelopes and can obtain temperature, humidity and moisture content.