How is air processed in a central fan system?

In a central fan system, air is processed at a central location and then distributed through ducts to various parts of a building. This method allows for consistent temperature control, improved air quality, and the ability to regulate humidity levels. The central location facilitates the use of various components, such as filters and heating or cooling elements, ensuring that the air circulated is conditioned appropriately before reaching the living or working spaces.

Distributing air through ducts is essential for maintaining efficiency and efficacy, as it allows for centralized management of airflow and minimizes the need for multiple units throughout a building. This system is designed to optimize comfort while ensuring proper air filtration, which also contributes to better indoor air quality.

The other options suggest methods that lack the efficiency and effectiveness of a central fan system. For instance, distributing air without filtering would not address concerns about pollutants and allergens in the air, while relying only on electric fans limits the ability to control temperature and humidity effectively. Additionally, relying on open windows for fresh air intake does not provide a managed air flow system and could lead to energy inefficiencies and inconsistent indoor air quality.