9. Reduce air pressure and clean the air with Air Vents
Most Japanese homeowners choose to install air vents in their homes. Firstly, they will help to control the air pressure in each room. Furthermore, they also act as an air filter. During the winter or rainy seasons, these vents will dry out the atmosphere in your room to prevent mold from forming. In 2003, they become one of the essential parts of the Japanese building code.
