JAUE2017-075: Study on the High Humidity in Underfloor Space of Detached Houses During Summe

Abstract

Many reports have been reported that floor insulated houses have high humidity in the underfloor space on 
summer. Previously reported1) say as the floor heat insulation performance improves, the space under the floor 
becomes low temperature and high humidity. And it was suggested that partition composition of the underfloor 
space the more complicated, the underfloor space will be the lower temperature and high humidity.
This study actually measures the underfloor temperature and humidity of floor insulated house of 10 buildings in 
Kitakyushu and investigate the influence of the floor insulation performance and the compartment composition of 
the underfloor space on the underfloor temperature and humidity environment.
The influence of the partition configuration of the underfloor space is large as a cause of lowering the temperature 
and higher the humidity of the underfloor space. As the foundation rises more and the partition configuration 
becomes more complex, the middle part of the underfloor space becomes low temperature and high humidity.
In a floor insulated house, forced ventilation is considered effective as a measure to improve high humidity 
under the floor during summer. It is considered operation control of ventilator depending on the condition of outside 
air humidity is better than all day ventilation. Confirm the effect of forced under-floor ventilation when the outside 
air humidity is used as the parameter of the ventilating fan operation control, and study optimal control method.
Ventilation fan operation control by outside relative humidity was effective for alleviating the underfloor high 
humidity. However, after July, forced ventilation throughout the day was about the same effect as when control is 
performed by outside air humidity.
Depending on the timing, the optimal control value for control of ventilating fan operation by outside air humidity 
changes, and it conceivable that differences according to buildings and regions.