An appliance with a Venturi based venting system is disclosed. The appliance includes a housing defining an airflow channel in flow communication with outside of the appliance, the airflow channel having a common channel with a diverging section; first and second heating units disposed in the housing; a first duct through which a first cavity of the first unit is in flow communication with the common channel, the first duct having a first outlet end disposed at least partially in the diverging section; a second duct through which a second cavity of the second unit is in flow communication with the common channel, the second duct having a second outlet end disposed in the diverging section; and a fan in flow communication with the common channel.