What is the required percentage of the floor area for the free area of a window opening in a bathroom?

The correct percentage for the free area of a window opening in a bathroom is indeed 5%. This is based on building codes and regulations designed to ensure adequate ventilation and natural light in smaller spaces like bathrooms, which often have limited airflow.

The requirement for 5% is significant because it establishes a minimum standard that promotes health and safety by improving indoor air quality and reducing moisture build-up, which can lead to mold growth. In the context of bathroom design, ensuring that window openings provide at least this percentage of free area helps to create a more comfortable and livable environment.

This specific percentage is typically derived from calculations related to the total floor area of the bathroom, ensuring there is enough natural ventilation to prevent odors and promote a pleasant atmosphere. Understanding these requirements is crucial for compliance with building regulations and ensuring that spaces meet both functional and aesthetic standards.