Choosing Best Airtight Options in Japan What kind of materials are available in Japan, where are they found, are they safe, how are they installed….? If you are looking to design, build or own a comfortable healthy house that consumes minimal amounts of energy then you may have searched and come across the following basic formula (no rocket science involved): 1. Airtight 2. Well insulated 3. Thermal bridge free (minimal heat/cooling energy loss at vulnerable spots in assembly) 4. Proper solar orientation (sun in winter/shade in summer) 5. Air ventilated (i.e., controlled fresh air!) Of course, correct and healthy doses of above (Passivhaus Consultants can help with this) cannot be achieved without the expertise of engineers, architects and builders or without the proper ...