What is the minimum percentage of floor area that must be glazed for habitable spaces?

Habitable spaces in a building are required to have sufficient natural light and ventilation to ensure comfort and promote health for occupants. The minimum percentage of floor area that must be glazed, which refers to the area covered by windows or other transparent materials, is generally established in building codes and regulations.

For most commonly referenced building codes, the minimum requirement is typically set at 8 percent of the floor area. This standard is chosen to ensure that these spaces receive adequate daylighting, which has been shown to positively affect productivity, mood, and overall well-being.

Having at least 8 percent of the floor area glazed allows for a balance between sufficient light and the practicalities of construction and energy efficiency. It ensures that the building remains comfortable and can also reduce the need for artificial lighting during the day, further contributing to energy savings. This threshold helps establish a baseline for livability in various types of habitable spaces, including living rooms, bedrooms, and other commonly inhabited areas.