1. Architectural design needs: air shaft is the abbreviation of ventilation shaft, which extends to the roof to remove residual heat and unclean air, and the external wall has air inlet and air outlet; If the wind well is facing the bedroom wall, it will cause feng shui interference to the bedroom.
2. Save the construction cost: If the air shaft avoids the bedroom wall, it is necessary to expand the size of the air shaft and increase the construction cost.