The Air-shiter is a new products possible ventilation at the same time cooling or heating with integrated refrigeration and ventilation units. and is a key component of the air shifter devices and bypass damper. The air shifter devices are to convert the outdoor air, room air, supply air and exhaust air flow. And the bypass damper is device to determine a ventilation. After research and development of these systems were as follows. It is confirmed that the Air-shiter is possible ventilation at the same time cooling or heating, and outdoor air cooling in the spring or fall.