The difference between a ventilation fan and an exhaust fan is mainly about how we use the words. A ventilation fan is a general term for any fan that moves air as part of a ventilation system. It may supply fresh air, exhaust used air, or do both in a reversible installation. An exhaust fan, by contrast, is a specific type of ventilation fan whose job is to pull air out of a room, process area, tunnel or mine airway.
In a typical industrial or mining ventilation system, there are several kinds of ventilation fans working together. Supply fans (or forcing fans) push clean outdoor air into the building or mine intakes. Exhaust fans pull hot, dusty or contaminated air out through ducts or return airways. Both supply and exhaust units are ventilation fans, because they are part of the overall air movement system. The distinction is simply whether they are handling intake or exhaust air.
An exhaust fan can be as simple as a wall-mounted axial fan in a workshop or as complex as a heavy-duty centrifugal fan extracting fumes through a filtered duct network. In underground mines, large axial fans operating on return shafts are often called main exhaust fans because they pull used air out of the mine. Their role is to create negative pressure and establish a flow path for contaminants to leave the working areas.
A ventilation fan may also be installed in intake shafts, airways or ducts to act as a main or auxiliary supply fan. Tube-axial fans blowing fresh air down a flexible duct toward a development face are clear examples: they are ventilation fans used in a supply configuration. Some tunnel fans and mining fans are designed to be reversible, so the same machine can operate either as a supply (ventilation) fan or as an exhaust fan depending on the required airflow direction.
From a design point of view, what really matters is the ventilation system as a whole. Engineers decide where supply and exhaust fans should be located, how much air each must handle and how pressure zones should be arranged. The labels “ventilation fan” and “exhaust fan” are mainly convenient ways to describe the different roles individual fans play inside that system.
In summary, every exhaust fan is a ventilation fan, but not every ventilation fan is an exhaust fan. A ventilation fan is any fan used to move air for ventilation, while an exhaust fan specifically removes air from a space as part of the overall intake–exhaust balance.
