Installing an exhaust fan in the garage is a good way to help reduce the potential for garage contaminants entering the home. Depending on the ventilation strategy in the home’s conditioned space, it may be a required component. For homes that utilize balanced or supply-only ventilation in the home, a garage fan is not required. For homes that utilize exhaust-only ventilation in the home (such as a timered bath fan), the Rater must perform a pressure test across the garage/house wall or a garage ventilation fan must be installed.