Every kitchen, bathroom and water closet compartment shall be provided with light and ventilation as prescribed for habitable rooms, except that the aggregate glass area in a kitchen shall be not less than six (6) square feet, and in a bathroom or water closet compartment, not less than three (3) square feet. However, where an approved exhaust ventilation system and approved artificial light is installed in such a manner as to be in operation at all times when any such room is occupied, no natural light or ventilation shall be required.