Which of the following is a requirement for the ventilation system in a dwelling unit?

A ventilation system in a dwelling unit plays a crucial role in ensuring indoor air quality and comfort. One of the primary requirements for such systems is that they should operate continuously. This continuous operation is necessary to effectively manage moisture levels, eliminate indoor pollutants, and ensure a steady flow of fresh air throughout the space. By running continuously, the system helps maintain a consistent environment, reduces the risk of mold growth, and enhances the overall quality of air, which is essential for the health and well-being of the occupants.

While options suggesting manual operation, inclusion of a heater, or energy efficiency may be relevant in certain contexts, they are not universally mandated requirements for dwelling ventilation systems. Continuous operation stands out as a fundamental necessity to ensure effective ventilation and compliance with health and safety standards.