You need fresh air to vent the toilet. When the fresh air is needed, the best is to have the wall of the toilet to face outside.

Mechanical ventilation is not advisable, the best is natural ventilation. Mechanical ventilation usually will only be in used when you switch on the light. When the toilet not in use, the humidity will built up in your toilet. The ceiling in your bathroom will grow molds easily.

The best is to wall facing external . If can’t be avoided, a mechanical ventilation system need to be introduced.