What is the requirement for natural light in habitable rooms?

In habitable rooms, the requirement for natural light is that there must be at least one window or a door that allows natural light to enter, which should provide light equal to at least 8% of the floor area of the room. This standard is established to ensure that occupants enjoy sufficient natural illumination, contributing to their comfort and well-being.

Natural light is essential for creating a livable environment, reducing reliance on artificial lighting during the day, and also aiding in the psychological comfort of the inhabitants. The 8% criterion is a measurable way to maintain this living quality while ensuring that the room stays within reasonable limits for light accessibility.

Other options might misinterpret the specifics of the requirement. For instance, suggesting a window equal to 10% of floor area, while more light is generally beneficial, exceeds what is typically mandated. The requirement of at least two windows in opposing walls might not be feasible in every room configuration, and a skylight alone may not meet the standards if it does not meet the specified light percentage relative to the floor area. Thus, the stipulation of having an option of a window or door at 8% of the floor area is both practical and functional.