Yes, HVAC systems require a vent in order to properly circulate air throughout the home. The vent is typically located in the attic or outside of the home and is connected to the HVAC system. The vent allows air to be drawn in from the outside and then pushed back out into the home. This helps to keep the air in the home fresh and free of pollutants. Additionally, the vent helps to regulate the temperature in the home by allowing hot air to escape during the summer and cold air to enter during the winter.