Is it mandatory to install a ceiling fan? Building a basement shower in a room with a window?

Our Building Code mandates ventilation in every bathroom. It can be window, exhaust fan or both.

Unless you like taking showers in the middle of winter with open window - I suggest that you install both window and exhaust fan.

Panasonic exhaust fans are the best and run at as little as 0.2 Sones. You purchase fan based on the size of your bathroom