Ventilation fans do not necessarily have to be on the outside, but it depends on the specific ventilation system and the purpose it serves. Ventilation fans are designed to improve air circulation, remove stale air, and introduce fresh air into a space. Whether they are placed on the outside or inside depends on the type of ventilation and the location they are intended to serve.
Here are a few common scenarios for ventilation fans:
Exhaust Fans: Exhaust fans are typically installed on the outside of a building or in specific areas such as bathrooms, kitchens, or industrial settings. Their purpose is to expel indoor air, odors, moisture, or pollutants to the outdoors, improving indoor air quality and preventing the buildup of humidity and contaminants.
Whole-House Ventilation: Some ventilation systems are designed to work throughout the entire house or building. In such cases, air is drawn from the outside and circulated through the interior, with the help of fans located both inside and outside the building.
Interior Circulation Fans: These fans are used to improve air circulation within a space. They can be mounted on walls, ceilings, or even placed on floors to move air around without directly exchanging air with the outside environment.
Attic or Roof Ventilation: Attic fans and roof vents are designed to remove hot air and moisture from the attic space. They are typically installed on the outside to pull the air out of the attic and create better airflow.
Window Fans: Window fans can be placed inside windows to draw air from the outside and exhaust stale air from the interior.
In summary, ventilation fans can be installed both on the outside and inside of a building, depending on their purpose and the specific ventilation needs of the space. Each type of fan serves a particular function in improving air quality and circulation in different environments.