Yes, an exhaust fan is an important part of an HVAC system. It helps to remove stale air, odors, and moisture from the home, which can help to improve air quality and reduce the risk of mold and mildew growth. Additionally, an exhaust fan can help to reduce energy costs by preventing heated or cooled air from escaping the home. It is important to ensure that the exhaust fan is properly sized for the space and is installed correctly to ensure optimal performance.