An airflow window is a system to improve solar blocking performance of windows. It is a practically beneficial system, however, still has a potential to improve the performance by controlling the air flow in the cavity between the glazing. In this development, we apply a Dynamic Insulation technique into the cavity of the airflow window. CFD analyses were carried out to measure the thermal performance. The results show that declines in the solar heat gain coefficient as well as the surface temperature of the inner glass were observed. The effects improve the radiant environment at perimeter zone in office buildings.