The requirement for natural ventilation is what percentage of the room's floor area?

The requirement for natural ventilation in residential buildings is set at 4% of the floor area of the room. This percentage is grounded in the need to ensure adequate air exchange, which is essential for maintaining indoor air quality and comfort. Natural ventilation allows fresh air to enter the space while expelling stale air, which is particularly important in habitable rooms such as living areas and bedrooms.

The 4% figure is established in building codes to balance sufficient airflow with practical design considerations, ensuring that windows or other openings are adequately sized without compromising the structural integrity of the building or leading to excessive energy loss. By adhering to this standard, inspectors and builders can ensure that homes meet health and safety requirements related to air quality while also providing occupants with a comfortable living environment.