No, the core of the fresh air system is to replace air, transport outdoor fresh air indoors, increase indoor oxygen content, discharge indoor harmful gases such as carbon dioxide, and filter indoor harmful substances such as carbon dioxide, dust and bacteria. If there is no exhaust function, only intake air, then the harmful gases in the room are not reduced, and the integration with the replaced fresh air does not achieve the function of purifying and discharging pollutants. So one in and one out is the best.